my buddy has a thinkpad x61 flip-around tablet, and it looks as usable as my thinkpad x60s non-tablet as a laptop, and it also looks like a reasonable tablet. (now, I'm not a tablet guy, so I can't evaluate how good a tablet is; the form factor is simply Not For Me. but my buddy likes it. he runs windows on the thing.)

Me, I carry a (non tablet) thinkpad x60s running Linux. it gets maybe 4 or 5 hours on the extended battery, and I carry one extended battery and two (half the charge) regular batteries. (I'm a big guy and the thinkpad x series is small, so the extra weight doesn't really bother me. It's still lighter than my girl's giant T series laptop w/ extended battery. That thing is heavy.) Also, the thing is cheap enough that I don't get too bothered at the idea of it getting destroyed.