I prefer CSI Miami.
Vegas doesn't have anybody that really grabs me enough to want to keep up with it. On NY I find all the characters completely unappealing in any way. I like Gary Sinese generally but even he seems cardboard in CSI:NY.
I like Miami mainly because of Emily Proctor (the southern belle). I think she's just gorgeous and really liked her when she was on West Wing as well.
It's also fun to keep a tally of how many drinks i would have taken if i'd been playing the David Caruso drinking game. 1 drink every time he puts his hands on his hips and 2 drinks for a dramatic sunglasses removal.