I tend to just use mine to play the official games. However, I use my Gamecube with SD Loader for all my retro gaming
While I'm still thinking about it, I managed to score Virtua Tennis, House of the Dead 2, and Shenmue (with all four discs) at a nearby flea market for a grand total of...$9.45. Unfortunately HOTD 2 doesn't work that well, but I still think I got a good deal.