I finally got the upgrade to Gmail's new interface and I'm quite pleased with what they've done. I'm not sure I would call it Gmail 2.0 since the contacts section is what got most of the attention, but it definitely needed some love. Aside from the nice new upgrade to contacts, I'm glad they finally made the mouse hovers more useful. I always thought it was pointless just to show me their email or picture.
The old and useless version:
The new and improved version: