I have just bought the catalyst theme which I believe used to be called Frugal.
I must say I am very impressed as for so long I have been looking for a real customisable wordpress theme. A lot of people use the Thesis theme and that is good but I must say Catalyst Theme to me seems to be my favourite.
Pros:
Easy to use
Can pretty well replicate any wordpress theme (or keep the bits you like)
Custom CSS, custom widgets and hooks.
Cons:
You need to be creative to use and make it look great, as I am logical person rather than graphically creative I am better taking a pretty theme and tweaking it, but I must say the simplicity of adding content and images anywhere makes it excellent value.
None others I can think of at present.
