Really like 4.0, especially the new organization for the live shows, ticket stubs, etc. The "Did You Know" section is a ton of fun, and despite others complaining about needing to refresh to see a new fact, I thought this was an essential part of it, as it ensures one doesn't see more than one fact (generally speaking) per view. (I look forward to the fact that for over 100 days, I'm gonna have a cool new fun fact to look at)
I really like the Meteora theme, but didn't care too much for the others. I thought the forum's went toward less trendy (web 2.0 look) to a more LP cultured look. I for one don't mind this change, but some may see it as a downside (potentially new comers)
Only responding because was asked what you like / don't like, and either way I absolutely love the site, and as an LP fan for years, and having just recently discovered it, its a cool community.