Any Ivy League university.  Any of the major universities on the west coast, like Berkeley, Irvine, ect.  The east coast also has alot of good schools, like Rutgers, New York University, ect.  Basically, any of the top schools overall, will usually be good for Philosophy.  Let me tell you, graduating from, lets say, Harvard with a BA in Philosophy will allow you to go anywhere for grad school.  I go to a small college, so I will have to do an MA first.  But oh well.  For grad school, you can go to www.philosophicalgourmet.com for a ranking of the programs.

Depending upon your interests in Philosophy, this will determine which school you want to go too.  For example, if you are interested in any of these three areas:  Philosophy of Mind, Cognitive Science, Epistemology, or Philosophy of Language, then Rutgers is a good choice.  New York University is strong in all areas.  Basically, New York University is the fucking mecca of Phil grad programs.  It will give the various strenghts of the Phil grad programs at the Philosophical Gourmet.  

The University of Pittsburgh is basically the holy grail of American philosophy programs. 

SUNY Stonybrook is great as well, it's in New York.  You're going to learn a lot of analytical philosophy there, though. 

The University of Texas at Austin is also a top notch school, but a little less so now that Robert Solomon has passed away.