Thought I'd list my collections in terms of what I'd class to be large (100+ games), medium (30-99 games) and small (less than 30 games).
Large collections: Sega Master System, NES
Medium collections: PCE, Megadrive, GBA, PS1, PS2, Nokia N-Gage (!)
Small Collections: NGPC, Game Gear, Atari Lynx, Amstrad GX4000 (!), Sega Mega-CD
I'm sure I'll have missed one or two, but that's the general idea.