I have played all of them, except the arcade one. My favourite one is defeinitely Double Dash, I loved making combinations of characters. Randomly combining them was always fun. The Wii one was also really great but that's mostly because of the online experience I had with it. Good times. I have a bunch of videos of me and my nephew racing with Krazy and other TKO/HW people back in the day. That was a lot of fun. I hope MK8 will be fun, too...
Here's one of those videos. Krazy, you're in it.

By the way, here's a picture for your bike fetish, Jabba. Dasiy > Peach though.

NSFW I guess:
http://mariodrops.files.wordpress.com/2008/09/mario_kart_wii___biker_peach_by_sigurdhosenfeld.jpg