Just water for me. I keep a cup and a big jug of water next to me at all times while at home (otherwise I always have a water bottle on me).
I don't know how to make coffee so it doesn't taste terrible. Though caffeine simply doesn't work on me anyway (damned body chemistry), so I definitely don't feel the need to drink it if I'm not getting any of the benefits. Also I really hate how it makes me smell (especially when I go to the bathroom... like how do people stand that? - and on that topic, how it acts as a laxative is pretty annoying), days after drinking just one cup and my body still smells like the coffee, so gross.
Occasionally I get really into tea, but the need to constantly go to the bathroom gets annoying really quickly. Also, like coffee, doesn't leave a good taste in your mouth (really promotes good habits with brushing your teeth, lol).
As for alcohol: I would love to get into casual drinking but just haven't been able to yet. Beer for me is definitely an acquired taste, and currently I haven't been able to work up to drinking more than half a can (literally every sip causes me to gag). Liqueur doesn't bother me so much, but I reserve that for parties (I tried drinking a gin and tonic yesterday at home but didn't find it very good, I definitely need to be around friends for that type of stuff). I think sometime in the next month I'll start (force) drinking a can of beer per day so I can work up the taste for it.