I used to get awful numbness in my hands, couldn't turn the key to open my car! I switched to Specialized Body Geometry gloves at first, which I still like. Now I'm using Louis Garneau Ergo Air gloves.

http://www.teamestrogen.com/products.asp?pID=2704

I tried the women's, they didn't fit me, too tight, so I bought men's and they're great.

While shopping for gloves, LBS guy told me many people have hand problems due to too much padding! Make sure that's not your problem. While riding, coast and shake out your hands occasionally, this helps me too.