ah, but of course! i always try to give it to them at room temp. maybe i should start giving it to them luke warm (so it feels neutral to my touch and body temp). they probably like it like that. i never water them with cold water though. it's usually in the middle, but will feel a little cool to the touch. not that i'm over analyzing this or anything......lololololollolol, but thanks guys. you guys rock
Body temperature warm (37°C) water wouldn't be a good idea - it would increase energy demand in the root system without increasing photosynthesis, and so could stress the plant.
One benefit to your plant from allowing water to sit for a day or so before using is that some of the chemicals often found in tap water can dissipate. Some plants are quite sensitive to chlorine, etc.
Most US municipal water is now treated with chloramine which doesn't evaporate. http://en.wikipedia.org/wiki/Chloramine#Uses_in_water_treatment