My favorite section is probably General Discussion ( http://www.mobileread.com/forums/forumdisplay.php?f=215
I like the depth and scope of our discusssions there. Reading Recommendations is probably my #2 favorite, as a source of reviews from people I've gotten to know a little.
Making it better is tricky. Sometimes I'd like to see more moderation but then I don't want heavy-handed moderation. Paradox. Okay, I am certain more fleshed-out and stickied FAQ posts would be handy to point noobs to, rather than rehashing the same topic in a new thread.
MobileRead is, in general, wonderful for scratching that same itch I have, a joy and lust for digital reading.