I try to go for at least 2 litres a day, but in this weather, I easily exceed that. I often have a litre right at breakfast time with my eggs. And it's always Brita filtered water, or water from the fountains at school. (That reminds me, in Europe, at least in Holland, there was a distinct lack of water fountains at the university, which drove me nuts because I was always looking for water!)
I found that the water bottle makes *all* the difference, at least for me!
I used to just use plastic water bottles that you buy in the store and just keep them and reuse them, but it wasn't always appealing to go fill those bottles up, for some reason. They were all crackly and the label comes off and then their sticky, etc. etc. So I went and got a 1 L Nalgene bottle and suddenly drinking water became even more fun! Sometimes my flakiness astonishes me!