I have a couple of generators as well, but the problem with generators is that they aren't always in everyones budget. Generators can get pretty expensive. This is why I usually suggest battery powered aerators. They're cheap, and will give you a few hour power on a pair of AA batteries (which most people already have set aside for emergency situations)
Also, I use the battery aerators for transporting fish. If I have to drive across the state to pick up a new fish, a cooler full of water and an aerator make for an easy, worry free transport.
Gotta love milti-taskers.
But if it is within your means (financially), a generator is a great investment.