I'm leaning towards reccomending Mass Effect. I'm naturally a Bethesda junkie- have been since I first picked up Morrowind and, subsequently, Daggerfall- but I thought Fallout 3 fell way short on a lot of things. VATS makes the game too easy and usually leaves you too reliant on it unless you drop your agility to 1, the difficulty slider's XP boost is nifty but also leaves the game too easy- you'll get to 20 before you know it, and then you have no gear upgrades or leveling at all after hardly any exploring. The replayability is virtually DEAD, specifically for the reason that while you can't do everything proficiently well in F3 from the get-go, you can do everything. My entirely min/max'd melee character (awful with guns) could still sufficiently kill things with heavy weapons, explosives, and small arms, leaving a deep emptiness or want to really make a new, specialized character. It's not just comparison to Oblivion/Elder Scrolls, it just fell short on some things that make it really gamebreaking.
Mass Effect has it's flaws (OH BY GOD, IT HAS IT'S FLAWS) but one of the MAJOR things important to our current-gen it didn't truly skimp on was replayability, from my perspective. There's not really any consequences (good or bad) for going good or evil, but there's literally not any in F3 either. The six jobs (pure gunner, pure techs, pure 'magic', and then three hybrids) do at least make you want to replay with a different specialization; I played quite differently between full tech (who could disable the guns and shields of enemies on whim and take them out) and the biotics (who could throw crowds of enemies around and then had to run screaming back behind the companions while it recharged). The game has a good amount of exploring to do on the minor planets (less than F3), the plot is top-notch (F3 fell way short, I'd say. Won't go into details, but you don't do much of anything in the end), and the combat is significantly more challenging and entertaining (it does like to take pot-shots every now and then with rockets, but if you play TF2 on eGO servers I'm sure you're used to getting randomly killed by snipers.

). Plus, Mass Effect has a tank.
Leave it to Cupcake to blow the thread out of the water.