One minor thing that always annoyed me in Live. It's a bit better now with reduced countdown timers, but it's the fact that ANY keypress cancels the logout. I'm used to tabbing out while the countdown runs. Sure, it's only like 15 seconds max, but 15 seconds too long to be staring at the screen unable to do anything. I wonder if it could be changed to, say, esc cancelling it instead of any key...
For that matter, this is the only MMO I've played where esc doesn't bring up the menu. Gotta hit \ instead. There's a lot of fiddly stuff like that that doesn't jive with UI norms...