I've decided to stop with the Dreamcast generation, tough exceptions exists. Although I won't collect for Playstation 2 or Xbox, i will collect (as much as possible) for GameCube games. I find them to be somewhat of an oddity for some reason.
Another exception is DS games, though that does not mean I will amass thousands of copies. I just try to get what I can, since many times I get them cheap, like when they are being liquidated at work. Otherwise, I skip them.
Also, I decided not to "collect" games I know I will never play, even for older consoles. I realized thst even if it's a hobby I enjoy, it's pretty much worthless to buy games that will pretty much rot in a shelf or to shell out insane amounts for a game I will never play. I realized this while trying to get a full Colecovision set. Now I just get the games I really want to get, and not spend 2K monies on a game I will never play.