Have you tried changing the temperature? Other flavors? Rather than going the Mio/Crystal Light route, have you tried just fruit/herbs/vegetables? Many people sugest cucumber, but my favorite recipe is basil/lemongrass. I make a concentrated tea, and then water it down so its just a light taste. Added benefit is that both are growing in my yard! Parsley is different, but also good.

Do you drink herbal tea? Is there a favorite that you could make weaker? My aunt use to make use Lemon Zinger Tea as kids and called it Kool - Aid, we were none the wiser

The Just Lemon family (http://www.truelemon.com/) is good too, sorta like the Crystal Light stuff, but without the artifical sugar (maybe that's the taste problem?).

Maybe watering down the juice you normally drink (and save calories/carbs!)?

I was the same way, pre-surgery I drank 1-2 gallons/day (I live in FL - hot climate), and rarely anything else other than herbal tea or alcoholic beverages. I find now I almost always have to flavor it, can't drink it very cold, or very hot. I pretty much put Special K or unflavored protein + other flavoring in everything. Helps get protein in as well My favorite recipe of late has been 2 scoops Syntrax Nectar Medical + Whey Protein Isolate + Coco Hydro - Instant Coconut Water Electrolyte Drink + clear fiber + flavoring of choice into 24 oz of water. Its been my "bedtime" water that I drink from all night since I tend to wake up with a dry mouth from my CPAP.

Hope this helps!