I agree, the shotgun is a really fun weapon, nothing like coming up behind someone at point black range and of course the TOMMYGUN. For life or death circumstances I prefer the turbo plasma rifle, bozar, gauss rifle, gatling lazer etc.
When I first played fallout 2 I was EXTREMLY lucky and got the shotgun really early, I reigned havok,everytime I would shoot an NPC in the back and hide at the side of a door, good times,
You may laugh, but I'd say spear, especially in F2 - it fits a tribal not knowing what it's really about just perfectly, even if Chosen One is wearing an APA.
Every other weapon is just an unnecessary addition .
My favorite weapon, at least in Fallout 1, is the assault rifle. Its boring, but it was pretty much my main gun for 90% of the game. Plentiful ammo, packs a punch and causes the occasional hilarious death. Winner in my book.