I drink tap water exclusively. I don't like bottled water. I do prefer my water cold, though, so I fill a bunch of bottles I have from different beverages I have drunk in the past, fill them with water and put them in the fridge.
I like SmartWater for those reasons too! Luckily I live in an area with really nice tap water, as well, so I only buy it when I'm out and about. SmartWater isn't super overpriced here, either - the first time I had it I actually bought it because it was like 40p cheaper than any of the other single-use bottled waters :P