Don't play regularly anymore. Working on that.
Have, at some points, played over a dozen different systems.
(Okay, some were just different "editions".. But when you rework the entire rule sustem from one edition to the other to the point where even your fans wouldn't notice if you just took a completely different game and slapped your name on it then I count it as a new game, okay?)
Of the two you mentioned, I recommend D&D.
I only know of one Fallout PnP game, and that game literally uses the same system as the Fallout games.
Using a system that is based on having a computer calculate everything for you so you can focus on other things is NOT a good idea for pen and paper because that means YOU have to sit around for five minutes every time you try to hit a fire gecko because the game master has to bring out the TI just to find out where you hit it.
Otherwhise White Wolf make good games.
No wait, the made A good game, and about a billion completely different settings for it because every game they've made uses more or less the same system.
Anyway, I recommend World of Darkness if you want something emo grimdark, or Exalted if you want anime-like "JUST GIVE ME ALL THE SUPERPOWERS ALREADY! MY POWERLEVEL IS OVER 9000!" kind of characters with over the top action. (Seriously. Your characters are pretty much demigods... At level ONE.)
(And I think this post sounds kind of angry.. Sorry about that. I've been rewatching too many of the old Zero Punctuation lately.)