Overall, Intel makes more power efficient CPUs than AMD.
Forget the FX series, they are basically power hogs so when comparing CPUs on power consumption consumption alone. It's best to compare Intel's Pentium G/i3/i5/i7 to AMD's Llano/Trinity APUs.
Simply stated, when idling AMD's Trinity APUs consumes around 7w less than Intel's CPUs. The exception may be the Pentium G series; due to being "cut down versions" of the Ivy Bridge architecture, it likely consumes a little less power than the i3/i5/i7 CPUs, thus narrowing the gap with Trinity. However, once the CPU (or APU for AMD) starts doing any amount of work, then Intel's CPUs definitely consumes less power.
So....
Idle and "sitting pretty"... AMD uses less power, but only around 7w, maybe 10w.
Doing any amount of work Intel consumes around 10w - about 40w less power depending what is being done. Watching a movie... 10w difference. Playing games... likely about 40w difference... if not more...