Wellll, that depends on who you ask. All you need is a 35 - 50 repair skill to do some 3second repairs to a weapon and make it useable enough to be effective. You could even get irradiated in Megaton for the easiest DR19 armour from moira. There's a hunting rifle right outside springvale school, which is a nice medium tier weapon for the early game. Raiders with .32 pistols make ammo pretty common. Leather armour you'll be able to get from Klamath provided you're got the wealth for it, and that requires a fair bit of hoarding in and around the immediate area. The effort to reward ratio is alot tighter in FO2s early game.
My point is, when it comes down to it, combat in both games becomes ridiculously easy if you make the choice to build up your skills in a way that will make the game easy. The trick to making all of these games a challenge is to limit yourself. After all, you don't have to get the jumpsuit from Moira. You don't need to go get that hunting rifle. The same goes for Fallout 2. If you know where to go, you can get medium tier weapons very early in the game. Hell, at least you can't beat fallout 3 in 18 minutes [search the web]. I'm not trying to say that any of the games are better than any other, I'm saying that they are about equal in their difficulty. It's simply that you level faster in Fallout 3 faster, maybe because combat moves faster due to the FPS style compared to turn-based. But in any of the games, you can become a god around level 12 if you want to be.