Yup. I've got a Gateway convertable tablet. I chose it mainly because it has a glass screen instead of acrylic, which is what Toshiba used. 18 months ago, those were the only two contenders worth mentioning.
I find that I really don't use the tablet mode that often. It's neat and works well, but I type faster than I write. I used to at least jot notes down on it during games, which worked pretty well. Once I switched to PCGen to track stats and initiative, that went away, too. Java does not play well with the handwriting recognition engine.
As a player, where you aren't anywhere near as likely to be randomly adding/removing things from the line-up, it might work a lot better. With HeroForge, it definitely would. Actually, I'm going to go with it working quite nicely for a player. I only did so for one session, but it was nice.
I have been known to sit in front of the TV and scribble game notes, but TV time is pretty sparse in my house and it's usually a couples thing.
Civ 3 works like it was built for a tablet, BTW. Beautiful interface. Civ 4, not quite as much.
Anyway, if I had it to do over, I'd probably spend the extra cash on a more powerful system rather than the flip-top. I could see the use, but my lifestyle really doesn't call for it.