I downloaded the Mix and Match theme real quick to try out and wow!!!! I really like it.
It uses Fusion as a base theme and to get all the bells and whistles, make sure you install Skinr.
1) There are some default color schemes you can pick from
2) Enable rounded corners for blocks, including the radius (3px, 7px, or 11px)
3) Overall, very easy to configure. Lots of options. Nice look.
