PS1. Few games I'd want don't run well enough on PS2 to get by.

JVC X'eye. Bulkier, arguably less reliable, and has lower compatibility than its distant cousin CDX. (power base converter won't fit X'eye, plus Everdrive's SMS rom loading is effectively broken on it)

Super Famicom. US models are so easy to mod for JPN games I have little interest in the system unit itself now.

Neo Geo AES. Much of the library is expensive. Once I can find somebody to consolize my MVS board that'll lower its appeal further yet.