64 is the best by far, and the 3DS version is the way to play it.
Star Fox Adventures is also a good game. It's way more like a Zelda game than a Star Fox game, but it's still good for what it is.
At the risk of invoking the wrath of the community I also really enjoyed Star Fox Zero. I actually like unique control schemes, and I found this one to be interesting and work well. Because of its reputation you can buy a copy for dirt cheap, so I think it's well worth the 5-10 bucks to give it a try.
Agree with all of this. Star Fox 64 is still the gold standard, and Adventures is a fun action-adventure spin-off.
I'll also invite the wrath of the community by defending Star Fox Zero. The control scheme was tricky at first but I learned to really enjoy it.
Finally, I'll send a shout-out to Star Fox Command, a DS title that has some interesting strategic elements mixed in with the classic "all-range" gameplay.