I use iKlear, yeah it's a bit pricey but the bottle of cleaner lasts a good long time, and you can clean more than just the screen with it (don't use it on the trackpad though, it says, just use the dry cloth). It comes with a nice big cloth, as well as a smaller travel size cloth and travel wipes.
I've read that it can leave residue on the glossy ones, but someone said it comes off if you just rub it a lot, and it is considered "polish" so it could be that the glossy ones just require more polishing because they're glossy (makes sense to me).