Game Gear. I think I got mine in 1995 with 5 or 6 games, the only ones I remember are Shinobi, X-Men, and Riddick Bowe Boxing. It is the only gaming item I do not regret selling or giving away. I still have my copy of X-Men only because I couldn't find it when I sold the GG and found it at the bottom of a box in the garage a few months ago.

I would probably buy one if I found it in the wild for $10 or less, but I'm pretty sure I would never actively search for one.