I'm an 88 baby, so pretty close. Nostalgia plays a big part I'm sure, but overall I'd say that n64 was a sweet spot in 3d gaming of function meeting simplicity. Because 3d gaming on console was so new at the time you get a good mix of games either playing it super safe, or really going nuts trying to stand out.
Overall I think you'll find that sequels on the system stand out quite well. Tony hawk 2, extreme g 2, Majora's Mask especially. They took what made the first games great and honed em.
I find the N64 fun in a relaxing kinda way. There's not much "hardcore" about the system, and I think that was largely Nintendo trying to lead the fun charge. Mostly quirky games.