John's! It's in the middle of those two. Ignore the religious stereotype, you won't notice it when you're there.
Um, I always really liked the look of Chad's, really nice and a good position. Cuth's has the best bar in the uni, but I think you might have a chance of being placed in Parson's Field which isn't on the Bailey (someone correct me if I'm wrong about that).
Mary's has a horrible, horrible bar. But that doesn't matter to a lot of people. I'd have thought it was more than 5 mins from the Bailey isn't it? Although I'm less likely to know than someone who actually is in it...
Edit: Personally, I'd prefer Chad's, for the position, and it's right next to Cuth's bar anyway...(and it has a nice one itself).
Maybe I need to think less about bars in colleges.
Also, joshm, I don't think Mary's will have any more females than males by now, they've evened it up since it let both in.