The 14 was much more comfortable to use on a plane (I flew much more often back when I bought it), but I rarely fly any more.
What I have done a lot of lately is take "working vacations" where my laptop becomes my only computer for a couple of weeks while my son and I decamp to my folks' farm on his breaks from school. I love that my job makes that possible, but doing it with the 14" laptop got old after awhile.
My son uses a 10" netbook -- more because it's a good fit for his 8yo hands than for portability. He's still a bit small to type well on a full-sized keyboard.
I've got a Sony VAIO Z, 13.1" @ 1920x1080. It takes a bit getting used to, but it's great to have a high-res screen for coding and also not have to lug around a huge, heavy machine.
My last laptop was a 15.6" beast (Core2 T7200 I think with a GeForce 8400M G), but it was just underpowered enough to not do everything I wanted when I wanted, and was too bulky and power hungry to be considered portable.
Last year I switched to an i5 desktop with more than enough CPU and GPU grunt to push through the most demanding tasks (such as video encoding). However, if i wanted to slowly hack away at some code while watching TV in the lounge with my partner or do some coding while at my parents place, I was out of luck.
To solve this problem I bought a AMD C-50 equipped Acer Aspire 522 the day they were available here. Despite having only a 10.2" screen and a "netbook" processor, I find it does everything I want to do with a portable computer. The battery life, size and weight give me great portability (+1 for couch-hacking). The dual-core APU never locks up or stutters, even when playing 1080p video via the HDMI port. The DX11 capable graphics even play WoW and Minecraft great at native resolution (1280x720), and allows me to hack around with OpenCL GPGPU programming from my couch. NOTE: I upgraded the memory to 4GB, i would recommend an upgrade to at least 2GB for anyone who has/is getting this laptop.
I definitely think switching to a lighter form factor with more portability has allowed me to get more done because I can literally have this machine with me at all times. That said, I waited for this laptop specifically because it was portable, cheap, and had a decent screen resolution. If i were recommending a laptop for someone, I would probably reccomend something in the 12-14" range, unless they're going to have a desktop to do the grunt work, as I do.
Currently I have a 14" Sony and a 13" unibody MacBook. Both are approaching 3 years old, so I've been trying to decide what to do about replacing them.
At this point, it's looking like the answer is going to be selling off the MacBook and (eventually) the Sony and consolidating into a single PC laptop. I have a reasonably powerful desktop for my needs (home-built Core i5 running Win7) and a nice Dell i7 laptop for work stuff, courtesy of work, so I'm mostly looking for a small and light enough personal laptop. I'm thinking I may just go small and cheap and leave the heavy lifting to my desktop PC, so I'm looking at some of the new AMD 'Zacate' E-350 systems that Engadget likes to refer to as "notbooks" -- probably the HP DM1, since it has one of the new clickpads on it.
I considered getting a MacBook Air, but decided not to. Even though they're very nice machines I'd really rather not pay the price premium, and I'm honestly not very enthusiastic about some of the things Apple is apparently doing with Lion. For the OS X-specific stuff I do -- mostly Ruby and Python in MacVim -- I can do it just as well in Linux and on the same platform I'd be deploying it on -- plus I can set it up to dual boot Windows and drop back into that if I want or need to.
I have a 15" currently - but I think I might make my next one a 13", for portability.
Lightweight means a lot to me - and if it's got great options for a high resolution and large external monitor then I'm happy. Hell, with DisplayLink technology nowadays, multiple external displays with a laptop is entirely feasible.
With the variety of resolutions out there, inches is the wrong measurement for me. I don't care if I'm working on am 8" or a 13", as long as I've got enough pixels to work with. I'm more productive on the 11" Macbook Air than the 13" Macbook Pro, because of the shape and resolution of the screen.
My complaint/concern has to do with deeply recessed keyboards. Whenever I'm not in an "optimal" location, e.g. a conference room, café, etc. where work surface heights tend to be higher, the front edge ends up pressing into my wrists.
I've found it frustrating that so many laptop designs have incorporated this aspect. Smaller body sizes tend to help, although the 13' Mac and Mac Pro nonetheless still seem to have it in spades. Also, widescreen formats have made the overall "depth" that they have to work with, when shoving that keyboard to the back, less -- although I'd prefer more vertical in the screen dimensions, and designers nonetheless get the keyboard too far back for my comfort.
(I strongly dislike actually having the thing on my lap.)
My last laptop was a 13", but it didn't have the power I wanted/needed. So I have a 15" now. And I consider it a desktop replacement. I can't wait until I can get 13" that'll do that. A couple more years and I think we'll be there.
I don't think you have to wait - Dell's little M11X AlienWare can do 16gb of ram w/ a core i7 in an 11", and less-ugly 13"s are doing iX w/ 8gb of ram these days too.
I'm moving more and more towards buying an Air and hooking up an external monitor to do "real" work. Two screens are better than one, and supreme portability and good battery life keep sounding better and better as I use my 15" MBP.
Don't get me wrong, I love the space on-screen. And I no longer have a TV, as it's large enough for my small living room. But all that really matters to me is an external screen port and a full-size keyboard. Being able to move it around and use it more places more often comes in soon after, and size comes much later.
I have an old Asus EeePC with a 10 inch screen as my ultra-portable
machine. When I travel I can throw it into a carryon bag and still have a
lot of room for other stuff. I don't mind the small screen that much; my
main gripe is the keyboard. It's just too small for easy typing. What I'd
like to upgrade to is a Thinkpad X100e. I think it will still satisfy my need
for exceptional portability, and it has a full size keyboard. I must
confess I also think its 11.6 inch screen will be somewhat nicer than
my current 10 inch screen.
Still tugging along on my first generation Asus EEE PC. It's 7.1". Tiny and slow compared to what's out there now, but it does the job I need it to do.
Not entirely clear if you are asking for what it is, or what we'd like it to be. I have a asus 1000he, and I think the ideal is 11-12" (i.e. just a hair larger). I'm considering upgrading to a Thinkpad x220 later this year, but I'm hoping someone comes out a non-overpriced SSD model with higher res screen (i.e. linux macbook air).
I'm happy enough with my productivity on 13 inch, I probably spend most of the time remote using it as is with occasionally plugging in a external monitor. One advantage for me is it forces me to think about my apps usability on a smaller screen as opposed to 1080p at home where its very easy to fit everything in.
I have a 10" netbook for personal use, which I take with me everywhere I go. I also have a 17" monster of a thing, which never leaves my desk because it's too big and too heavy to carry around with me. Going off the keywords "comfortable" and "portable", I'm going to have to pick the former.
I used 15" laptops for years, but recently switched to 13" and feel like it is a more productive screen size. I love dual monitors, but 15" seems just big enough to have distractions visible without having multiple windows usable. The 13" let's me focus.
Right now it's a 13" macbook pro. If I had an external screen or two at my home desk, which I have been putting off, I could definitely go even smaller.
I have done 15" in the past but it's not portable enough for me.
Hackers can use whatever they feel is the best platform for their hacking. I personally felt sick to my stomach dishing out the cash for a 15" MBP knowing I could get the same hardware for half the price from Dell, however I want to (eventually) do iOS dev so I felt my hands were tied. Otherwise I would have just put Ubuntu on a Dell and VM'd Windows.
The 14 was much more comfortable to use on a plane (I flew much more often back when I bought it), but I rarely fly any more.
What I have done a lot of lately is take "working vacations" where my laptop becomes my only computer for a couple of weeks while my son and I decamp to my folks' farm on his breaks from school. I love that my job makes that possible, but doing it with the 14" laptop got old after awhile.
My son uses a 10" netbook -- more because it's a good fit for his 8yo hands than for portability. He's still a bit small to type well on a full-sized keyboard.
(I voted both of my laptops, not his)