Man, the house I grew up in had a 1/3 acre lot, and it was miserable mowing that even with a self-propelled electric!
lurkette has this fundamental hatred of gas-burning tools. As a result, we bought a reel mower when we got our first house, which was on a 1/10th acre lot. That thing was endless misery. First of all, it's not just pushing, there's resistence in the wheels that gives the blades power to turn. So it's sort of a work-out. You also can't let the grass get too long, because if you do, the damn thing will just bend the grass over and not let it into the cutting area.
If you're looking for an environmentally and acoustically friendly lawn mower, check out the one I just ordered for use at our new house:
right here
It's an electric mower from Black & Decker with a rechargeable battery. It's a little spendy, but it's a super cool thing that is going to serve me well for years and years. UPS is alledgedly going to deliver it tomorrow.