Apart from the gas/electric question, placement is perhaps the biggest factor to consider when choosing a new oven. We've used both freestanding stove/oven units, and standalone wall ovens. Which do you have, and which do you prefer?
I've used both, but my last two rental homes have had wall ovens. (Tiny wall ovens, I'd like to point out!) I do like having the oven separate, as it keeps the stove area cooler; I hate those blasts of steam and heat that come out right when you're standing stirring a pot. Also, in my current home I have a gas stovetop and an electric wall oven, which I feel is a great combination.
What about you?
(Images: Oven manufacturers)