Unreal engine fo sho! Those video tutorials that come with it are golden. Don't try to do any fancy AI scripting if your not into that. It's meant for deathmatch. Anything other than deathmatch get a bit hard to program. But then again, I hardly knew Kismet and the documentation for it at the time was shit.
I'd highly reccomend UT3. It's the most standard editor there is. A huge % of console and computer games are made in this editor, and as other's have stated it's about as easy to get used to as you're going to find. When you're ready to actually get serious, tutorials are great and all, but you're going to run into…