Mario Kart Wii. It got rid of the ridiculous snaking and added the drift mini turbo thing. The game actually takes more skill than the others to play on a high level. Don't let others tell you differently. Also, the bikes are awesome and all of the classic tracks in the game are great.

I believe Double Dash to require the most skill (especially if the blue shell was removed).  The ability to hold 2 items at one time added a shitload more mayhem (additionally with the super moves that were unique to each character).  I believe it showed the most strategy even though there were cheap items in abundance.  Give me Toad/Diddy Kong combo and I can wreck shop all day on MK:DD.  Toad for the golden mushroom if I somehow fall behind and Diddy Kong for the big banana when in first.

I have destroyed all of the expert ghosts in MK Wii.  :p

If you want to see how difficult it is to race well in that game, take up TWRoO on his offer to send you some time trials.  He has the best on the site (except for a couple).

I'll have to pass and admit defeat the way you are pumping him up.  I believe my MK skills were top notch during the GC days (along with my Smash skills).  When playing MK:Wii online I usually end up in top 3.

But that's how you learn.  You learn to get better by watching the best.  At least that's what I think. 

I got much better by challenging his time trials.

Mario Kart 64. It just brings back so many good memories, and I absolutely loved the battle mode on it.

Haven't played MK7, probably the Mario Kart I had played more hours is Mario Kart DS, followed by N64 and then the original, however I vote for Mario Kart Wii. Online was incredibly fun, bikes were great, local multiplayer was great (when playing against the computer), the tracks are the best and some musics were great too. I have to say that local multiplayer between only 2-4 people was incredibly unbalanced and boring. Usually the last place would get the cloud which will make it impossible to win. Also the battle mode was terrible. Despite that is the one I liked more.

2) Next, very closely is Mario Kart DS, playing against 8 friends was amazing and fun, and I never had a problem with snaking, I love it. The problem is when you play against someone who is Extremely good at it and do it every second. I usually do it only in the curves and in a straight line when it's possible, but not every second.

3) MK64, snaking was really important for some shortcuts and that was the fun of it. Battle mode and 4 local multiplayer were great at the time. Great memories but I admit playing it today feels very dated, you have to get used to the slow speed.

4) Super Mario Kart was great at the time and I had a lot of fun, but today is impossible to play, the controls are very awkward, and you have to put a lot of practice in it just to control it right. Still I loved it and it the most challenging Mario Kart ever. Trying to beat it in 150cc Special Cup is a pain in the ass.

5) Double Dash, I liked it and had fun with it, but the tracks were kinda simple, my friends and I didn't had as much fun with it as with MK64.

3ds version.

Mario Kart 64 - Two Reasons.

1) It established the framwork for all 3D Mario Karts. Every time I play a new Mario Kart, I always compare it to Mario Kart 64, and judge where the game is better or worse.

2) 2 Player Grand Prix. Honestly I never play Mario Kart alone, for Mario Kart Wii I am forced to play GP mode alone to unlock everything. This is boring as hell, what is Mario Kart without multiplayer, and what is Mario Kart without all the bonus characters and tracks.

My number 2 is Mario Kart Wii. It has the most content compared to any Mario Kart game I have ever played (haven't played 3DS version), and I don't like playing Mario Kart on Handhelds because, again, I am playing it alone.

The Wii version is my favorite, but so far Mario Kart 7 is bouncing up and down, depending on if a blue shell hits me right before the finish line and costing me the race (again, and again, and again.... and again.....)

So my ranking:

1. Wii
2 (T). 7
3 (T). DD
4. DS
5. N64
6. SNES
7. GBA