I have this problem also, but find that with the right gloves and bar tape combo I get pretty good relief on long rides. I also took some of the pressure off by angling my stem upwards. Here are the gloves and tape I like:

Amazon.com: Cinelli Cork Tape: Sports & Outdoors
Men's ELITE Gel Glove - Pearl Izumi

Hope that helps!

Edit: Also, at REI, they have a really good return policy (if you're member at least). You can try the gloves out on a few rides and if you don't like them, they can be returned! Really helpful in that sense.