Out of those posts, I'd go for the Bianchi, it looks pretty nice.

However, red flags go off whenever I see a CL posting with only one picture of a bike, from the left side. The poster either knows nothing about bikes, and is selling the kind of crap bike that people who don't know about bikes own, OR, they know nothing about bikes, and have no idea they're selling a good bike for a low price. Caveat emptor.