Looking for a device to find out how many watts are on my AC circuit?

So I (think I) know I need a MultiMeter, but what I need is one to find out the draw of all my devices COMBINED thru wall plug. I have Plasma / PS3 / Receiver on one circuit; Projector / PS3 / Receiver / Wii on another; 2 computers / 2 monitors on another and all my DSL / Networking / External HD (and Misc other) on another. I also have several UPS systems. Basically I need to know how much each circuit TOTALS in order to optimize my UPS usage - because is my power draw is greater than the battery support, then it all dies anyway on power outage.

Basically, what I need is a device that I can plug into the wall, and plug my UPS into, that will tell me how much power that UPS is drawing (therefore, if it will be too much to support on battery - without crapping out my equipment to test it).

This is really just for home use, so I don't want to spend a lot on this.

Any ideas are appreciated!