The UTH's generally have pretty low wattage. I would say if it is indeed those items, that it would be the lamps. Also, have to account for the winter time. Maybe you have a drafty door or window(s). If you do think that it is these items, I would suggest the energy saving light bulbs from wal-mart. They only use about 13 watts, cost about 6-8 bucks for 4 of them, and put out the light of a 60w bulb.

My power bill doubled this past month. My normal bill is below $60. I have all energy efficient light bulbs in my 2 br apartment. Two computers with over 600w power supply's that run a good 16+ hours a day combined. Two 32" LCD monitors ( mine and my brothers ), an xbox that see about 3hrs a day play time, and 7 snakes with individual heat pads. I believe it was only high this time because my Central unit would kick on for 15 minutes and be off for 8 minutes before kicking back on again. I have that fixed now to where it runs for 15 minutes and off for 30-45 minutes before kicking back on. So next bill should be back to normal.

Sorry for getting side-tracked, but maybe my 'long-winded-ness' can still help out =)