I know that some of the Mac crowd love the small-screen options and my previous laptop was a 12" 1280x800, but I can't imagine working routinely on a screen that small in either inches or resolution these days.

The biggest question is how are you going to be using it? Mostly at a desk with an external monitor as well? On airplanes in coach? Any client presentations?

What I ordered earlier this year is a Lenovo T430 with the resolution bumped to 1600x900 ($+50) on a 14" screen; they now also have the T430s (slim) and T430u (ultrabook) which are both thinner and lighter. If you want larger, the T530 lets you go up to FHD (1920x1080) but at a significantly higher cost.

Looking briefly now, the T430u drawbacks include a limit of 8GB (probably a single slot), no mSATA or WWAN slot, and a display of 1366x768 with no choices. That last would've disqualified it for me immediately.

The T430s weighs a bit more and has more options, but also starts around $950 and that extra money really only buys you about 12 ounces less weight. I was looking hard at budget, so it also wasn't an option.

I'd recommend the T430 with a third-generation processor (specifically for HD4000 graphics). There's a nvidia option using Optimus, but I'm not sure how good it is under Linux (or whether it really buys you much performance). Bump the screen to 1600x900, bump the Wifi up to the 3x3 option (both things you can't really add later and which don't add that much to the cost). DO Add the fingerprint reader; smart cards and color sensors only if they fit your needs. Also add the backlit keyboard - you can't get it later, and when you need it it's really kind of nice to have. Also add Bluetooth up front. If you're ordering one, start with the lower model (not the "with Faster Processing" one), you can upgrade the CPU during the selection process but not downgrade it from the more expensive starting point. Starting from the lower model also lets you get Windows 7 (Home or Pro) instead of Windows 8 if you're going to keep Windows at all and don't like the Metro UI.

I stuck with the smallest HD and stock 4GB, adding another SODIMM to go to 12GB was dirt cheap, and I'm easily able to run KUbuntu in VMWare Player under Windows 7 Pro. You can replace the optical drive with a HD caddy for under $20 and have a second SATA III drive; you can add either WWAN -or- a mSATA drive (SATA II), there's some form of caching that can be set up with mSATA but I didn't bother. If you're going the full disconnected user route, you can add assorted battery options to get you up to (theoretically) 30 hours, 6-8 is easily feasible by just upgrading the stock battery - I haven't seen the "up to 9.7" with the 6-cell battery but I suspect that going to a SSD would be a big part of that.

After you get it, set up a power-on and hard drive password in the BIOS and configure the fingerprint reader under Windows to let you bypass those with a swipe. Throw on TrueCrypt and encrypt the entire drive as well.

One caveat with the newer ThinkPads, they did fiddle with the keyboard but it's still great. The big key I miss is the Menu key (right-click equivalent), but you can emulate it with Shift-F10 on Windows.

Physical keys that aren't present and workarounds:
Context Menu/right-click = Shift-F10
Break = Fn-B
SysRq = Fn-S
ScrLk = Fn-C
Pause = Fn-P

And finally the page/screen forward and back buttons were replaced and the pageup/pagedown buttons moved to be with the cursor keys.