Accelerade out of my bottles. I buy the powder online and then mix it in the water bottles before I go out. (I just moved into an apartment with a dishwasher -- this makes a huge difference, as the bottles taste funny unless you boil them or run them through the DW).
Note to curious: the accelerade tastes funny, but I feel like it works. The mix of protein and carbs, vs. just carbs (IE, Gatorade -- which I love the taste of) really does seem to add something, particularly on longer rides.
Might just be placebo, but if that works, then I'll take it, too!
Cheers.