Fallout 1 had my favorite plot (and villain!), but Fallout 2 had my favorite gameplay mechanics. And Frank Horrigan
As an aside, here's a story for you: I remember back in the mists of... 2001, maybe 2002? That era, anyway. Back when people still used a program called mIRC, which I doubt people born from the 90's on up will even recall.
Anyway. Back then, I had the fortune to have a chat with Tim Cain (Nice guy, by the way!), and he told me of his vision for the Enclave for Fallout 2. Which I recall was basically; Screw Earth, we're leaving!
I'm certain others will remember this as well.
Also, back when Fallout 2 came out, it wasn't that many years since Under a Killing Moon, and the whole plot of wiping the mutants off the planet had just been done. Don't get me wrong though, I still love Fallout 2 as well, but blowing up the bad guys' base before they can wipe out the world wasn't as original as the plot of FO1 was at the time. At least, not for me.
-Pharl Pirates, vampires, zombies, ninjas, ghouls, aliens, goblins, monsters, robots, sorcerers, undead, werewolves, demons, mutated dinosaur-cyborgs and those pesky phone salesmen! The shotgun is a one-size-fits-all solution!