Super Circuit was pretty bad. I went back to play it after I got Mario Kart DS, and it's so damn hard to control. I actually remember playing it with only Mario back when I first got it cause everyone else was so touchy.

Mario Kart DS is fantastic, and the original will always be up there (it's battle mode is still unmatched, as the IGN UK reviewer agrees), but as for 64 vs Double Dash...I don't know. It's been really hard to go back and play 64 after playing Double Dash :-\