WOW! Tons of great picks so far that I completely agree on specially the Quintet RPGs and Shadowrun SNES I love those games, but I'm here to advocate the greatness of Shadowman (N64, DC, PS1 and PC), is sort of in the style of Metroid Prime but in 3rd person and with very different themes, just play it it's awesome I believe it costs 20 $ on Ebay go with the PC or Dreamcast versions they are the best ones.
See also Re-volt it's an arcade style racing game in which you drive RC cars, it's so awesome that people are still playing it online and making mods for it even though it was released on 1999, with this one no question go for the PC version , though the other ones are good they lack multiplayer and mods.
I almost forgot, Body Harvest for the N64 was pretty awesome too, it was originally going to be the first M rated game published by Nintend but they dropped it because they're stupid, it's sort of like GTA but Sci-Fi with the setting of Apocalypse by giant bugs and even though it has very bright primary colours the music can be eerie enough at times to give it an scary atmosphere, that thing was awesome, and yes it was made by Rockstar, while we're at it the game that ended up being Ninten's first M rated game was pretty awesome too, but it's much more popular it's called Eternal Darkness pretty awesome Survival Horror, it's like if someone made Resident Evil but with a Lovecraftian theme, a good story and good controls, and I don't want to spoil the Sanity meter but try to never have it completely filled, the game is much more interesting if you don't fill it.