I'm not that big into racing games in general but have always had a good time with mascot car racing games. I have spent countless hours playing Mario Kart. I've extensively played them all up to 7 on 3DS. The only reason I haven't played 8 is because I don't have a Wii U yet but it will be a top priority to get whenever I finally purchase one.
Mario Kart aside I would say my favorite is Diddy Kong Racing. I really liked the adventure mode as the progression has a similar setup to Mario 64 and Banjo Kazooie. A hub world with areas to unlock as you progress. I hear Crash Team Racing has a similar setup as well. Seems with racing and platformers I always leaned more towards Nintendo 64 in that era so I didn't pay to much attention to the Crash series.
Mario Kart aside I would say my favorite is Diddy Kong Racing. I really liked the adventure mode as the progression has a similar setup to Mario 64 and Banjo Kazooie. A hub world with areas to unlock as you progress. I hear Crash Team Racing has a similar setup as well. Seems with racing and platformers I always leaned more towards Nintendo 64 in that era so I didn't pay to much attention to the Crash series.