Large... so much so that at some point my wife will probably want me to sell some part of it. Back at my parents place, we have 50+ Atari games, 50+ NES, 30+ SNES, 30+ N64 and even some Colecovision games. My personal collection is the more recent acquisitions, including 7 PS1 games, 30+ PS2, 20+ PS3, ~10 GCN, 30+ Wii (including 6 guitar hero and 2 rockband - plus 2 guitars, 2 drums, a mic and keyboard), 8 Wii U, ~20 DS + 7 3DS, 10ish GBA plus a few dozen VC and PSN purchases. Oh, and a few dozen steam games and the entire diablo and starcraft series, plus some older PC stuff. (If it isn't obvious, this has been a lifelong collection process...)
I guess I'd rather keep the systems and games as long as I can, but I usually buy new, but cheap, and almost always go through and beat each game, with a minimal backlog (notable exceptions have been MGS3 and 4, have tried 3 at least three times to stop - and Star Wars Bounty Hunter - the difficulty and my obsession over finding the optional targets...). I feel like I'd rather have them for my kids than sell them for large losses and loss of content that I may or may not ever get to play again.