I think hellgate london is overrated, and it hasn't come out yet.
I guess it may be over-rated. It isnt even rated though, because as you said, it isn't even out yet. It looks fun to me anyways.
I'd say that besides the obvious, FF-VII and Halo, I actually think that HL2 is a LITTLE bit over-rated. I mean, it's fun, yeah. Ravenholm was freakin awesome, but after a while it gets a little monotonous. Combine, Zombies, Antlions. The puzzles are fun, but to tell the truth, I personally had more fun in Far Cry and F.E.A.R. Not to say Hl2 is by any account not great, I just wouldn't put it on a pedestal above other great PC FPSs.