I have to admit I'm a fan of Evernote and think it holds the most promise. The biggest weaknesses/opportunities I see for it thus far:

Titles (Mike has already addressed this here)

Better Tag Filtering (Regular Expressions Perhaps?)

When I capture entire web pages, I'd like to go back later and mass delete canned blocks (il.e. banners) which would require some pretty extensive find/replace capability

Easier entering of tags...the rubber stamp tool is clumsy

Synchronization and Archival

I agree that tags are the way of the future. I don't want to deal with hierarchy any more. Delicious currently has my favorite tag implementation.