Mine's a humble 7.5 amp, plug it in the wall, tool-store cheapy - but it's got a good bit of power, has more than paid for itself in the year or two I've had it and they're fun - Especially when a diamond-tipped blade is added!!!
I just got the B&D 14.4 cordless nailer. Not as good as the dewalt cordless nailers, but then again, I'm not a contractor so I can't really justify parting with too much coin when I'm only doing trim, baseboards, etc... in my house only. Handy little thing though, and no toting around an air-compresser.