There are three types of mowers typically used by homeowners for residential lawn care: Gas powered mowers, electric mowers and manual push mowers (reel mowers).

Gas mowers are used commercially, but can be a headache for homeowners with smaller lawns. Electric mowers offer ease of use and operation and don’t have inefficient polluting engines, but sometimes cut quality is not as high as with gas mowers. Reel mowers offer great cut quality, but don’t bag grass and take sweat effort on the part of the operator (they are great for small lawns).

Some options for electric mowers on the market are:
Black & Decker and Yard Machines.
Hybrid electric reel mowers are also available.

An interesting idea for people who want an electric mower that will mow the lawn for them is this Robotic mower. How this works is a mystery to me, but if it works for vacuums, maybe it can work for lawn care.

For More:
Good listing of Electric Mowers from various manufacturers
A good overview of mowers at About.com