My room temps are usually 70 or higher since the heating system in my apartment sucks.
I use standard 24 watt compact florescent 6500K color temp bulbs and they add sufficient heat to get tank temps right.

Sometimes its trial and error to get these things right. Tank depth, room temps, how much heat is lost through vented areas all play a part on what bulbs will give you the correct day and night temps in your enclosure. Even raising and lowering the light fixture has a big change on tank temps.