I know someone who swears by Labourade! I plan on trying it next time.

I personally had mostly water, with a few primas inbetween. Whatever you have, make sure you take straws with you! By the time you're past 5cms you're going to want someone else holding your drink for you I really recommend keeping up your fluids (and food too, if you can), but like Ren, I didn't want a whole heap of sugar making me buzz, so I stuck to mostly water. I did manage to eat a bit too though, (snack type things) including jelly, which the hospital provided! I loved that, DH spooning it to me while I was in the bath!

And yes, make sure your support person knows to encourage you in drinking/eating, as you will probably forget yourself.