I still have 3 Atari 2600s, an NES, a Genesis, a Super Nintendo, 2 N64s, and all three of the current gen consoles, accompanied by a regular Gameboy, a Gameboy Pocket, a Gameboy Color, a regular GBA and a Nintendo DS.
I'm building a doomsday device. It's slow going since it's really difficult to get the architecture of a PS2 to merge with a GameCube and take commands from the Xbox CPU.
I will keep it until the system looses all relevance to me and the games I like to play. So until Gladius, Soul Calibur, and Culdcept make the jump to the next gen I will be playing them still on my PS2 (the rest of the games that I really like are probably going to cross over or have something similar available).