600,000 is equivalent to 600 completed games. Too much? Yea probably.
It's just that people like this pick up games like Avatar and King Kong to "complete" them. These games only take 2-5 hours to get 1,000 points in, and really are not that fun. To make 600,000 points, he had to play a lot of dull games.
P*nis Points.....erm, I mean achievement points are fun to get, but does total score really matter? When I play games on my 360 I try to get as many points as possible for games that I love. Halo Reach I have 1,400/1,400, Mass Effect 2 I will soon complete, and I generally try to get as many points as possible for games I love.
However I do this because it gives me a reason to play the games I love more. It's another reason to play Alan Wake on Nightmare difficulty, or another reason to pick up Forza and play another race.
Many games I don't like I have low scores, like Saints Row (10/1,000), and I don't care.
Gamerscore means nothing, it's just an ambiguous score. If yours is higher then someone elses, it just means you spent more time in single player, or just playing crappy games. It only means something per specific game. Sony realized this, and that's why PS3 has a Platinum Trophy, but they realized this too late IMO. MS realized this too, that's why thy give you a list of your completed games on one tab.
So is 600,000 too much? Hell yes, get a life....wait I should stop being on this forum too, to be fair.