I just bought a Look 555 and love it. I did a ton of research and why I chose that frame. You can get a good deal on one new on e-bay...'06 close out.
I too chose '07 Chorus UT with compact CF crank skelton brakes etc.
The biggest factor over and above aesthetics, finish, understated graphics, horiontal top tube....is the ride quality. This frame has the best ride of any frame I have ever ridden.
Good Luck,
George
P.S. Search function for some reason does not register Look frames...perhaps because the word look is generic...not sure. There has been a number of posts about them but the search function will not pick them up.