I drink about 2-3 liters of water per day. I re-fill a Camelbak or Nalgene bottle that I take everywhere with me. Started doing that in undergrad and it works perfectly for me. No excuse not to drink it, and I love that the bottles are lined and tell you how much water you have consumed.
I really only drink water. I love coffee and have a few cups most mornings. Never drink soda because I can't stand the taste. I like some juices, and I'll occasionally have sweet tea (this is the South, after all), but I prefer water over anything else.