I don't think "ego gaming" is any edition, or any rule-system specific though.
The one time our group took a small diversion from D&D and tried GURPS, the gamer in our group who took to it more than anyone else was the one guy who consistently "power gamed," and to me, "power gaming" is one form (albeit an easily recognizable form) of "ego gaming."
Because GURPS is waaay more fiddly with numbers and stat assignments, he took it as a personal crusade to "break" his character, using ranged weapon combat focuses. For him, it was never about really "playing" the campaign/sessoins, it was all about getting put into situations where he could show his "awesomeness." The GURPS system fed into it; the problem was further exacerbated by the fact that the GM was totally unfamiliar with the rules system, and didn't really know how to counter it. In this context, this particular player only wanted to "enjoy" the feeling of "being awesome/accomplishment."
Now some of you may say, "Why do you let that guy play in your group?" Well, the answer is, he's a friend; I've known him for years, and the GM has too, and outside the game he's a funny, intelligent guy, but he's always been just "wired" this way when he plays RPGs. In D&D 3.x, the GM could keep it in check, for the most part, because the GM had an absolute mastery of the 3.x system. He's literally the kind of player that will have his character walk into a weapons shop, talk to the merchant, find out what the most valuable stuff in the place is, and then come back at night and either steal it, or just beat up the shopkeeper and take it.