I'll never forget 007 Goldeneye for the N64
Haha yeah! I remember playing that game for hours on end, both single and mutiplayer. At the time, it was awesome.
In the case of both Goldeneye and Perfect Dark, they would have all sort of lasting power, if it wasn't for the technical aspects of the games. They both have fairly low frame rates (especially Perfect Dark), and multiplayer games seriously suffer because of this fact. Try playing a PC shooter at 2 - 5 Frames per second and see how much fun that is.
That was the major downfall of the N64 - the system couldn't handle the games. Lots of awesome games got destroyed by the lack of playability brought on by the low framerate. Goldeneye, for the most part, was alright, framerate-wise, but the odd single-player, and many multiplayer situations caused enough choppiness that it degraded the playability of the game. Perfect dark was even worse for this.
At least for me, the framerate took away much of the multiplayer, and even single player fun of Perfect Dark. I always played Perfect Dark on low-res (even though I have the expansion pak to go high-res) because the framerate was slightly better.
Aside from the framerate, both games were absolutely awesome, and I would have played them more.

The framerates, espcially Perfect Dark's, finished me on the game, I must admit.
When I play PC games, I keep the detail down to maximize the frame rate of the game. Nothing messes my game up more than a low framerate.