Another vote for Endurox R4. Drink it w/in half an hour of finishing your ride. Steer clear of the lemon-lime. I like the fruit punch, haven't tried orange. It seems pretty expensive, but it's not so bad if you work out how many servings you get from a container. Performance almost always has it on sale. Also, if you go to the Endurox web-site, they almost always have a $2 or $5 rebate coupon.

Finally, Joe Friel has a recipe for a homebrew recovery drink in the April '02 Ultra-fit e-tips. Check the first article, "Quick Recovery."