Personally, while I thought Mario Kart Double Dash had a neat mechanic, both me (a MKart fan) and a friend (a racing game fan) thought the overall game was rubbish.
Most people violently dislike Super Mario Sunshine. I gave up on the Mario games after the SNES era, so I haven't played it myself.
There were two major Zelda games. Wind Waker had a controversial art style shift that kept several gamers (myself included) away from the game. The reviews that mentioned there were only three dungeons and tons of backtracking and hours upon hours of sailing around, doing nothing, didn't help its reputation. You might want to look into it before you spend any money.
The other was Twilight Princess. While I did pick up this game, it was unbelievably boring. ("Seriously? A fetch quest for a cat?") I guess people liked it a lot better than Wind Waker, but I just couldn't bring myself to care about it and gave up a dozen or so hours in. Like another poster, I really don't care about the series anymore after those two misfires.
As I have all 4 of these games, I'll chime in with my opinion.
I like Mario Kart Double Dash. It's a little bit different, so I can understand if you didn't like it as much. The game is only really good in 2 player imo, otherwise you're at a disadvantage in the more difficult races, and it
is a more difficult game. Personally I'd still recommend it to any Mario Kart fan, but that's my opinion.
I didn't get extremely far into Mario Sunshine, although I liked what I played. I found the platforming levels extremely annoying and frustrating due to the very touchy controls, and that's why I gave up on it, but aside from that, I found it about as enjoyable as Mario 64.
I was hugely turned off by the art style of Wind Waker, like many others. And the more I played it, the more I disliked their choice of direction. The first 3/4 of the game are great, but the sailing kills it as much as everyone says. Just when the game gets good with 3 amazing dungeons, the game is basically over and you're stuck sailing boringly for the final 1/4 - 1/3 of the game. It's like having sex, but right when things are getting good, she stops and tells you to take a sail boat across the Atlantic Ocean instead. It shouldn't be too hard to pick it up at a reasonable price, so I guess it's still worth it if you're a Zelda fan.
Twilight Princess took some time to grow on me. I can understand if you gave up, because it took a long time for me to really get into it too, but as I got into the second half and decided to explore a bit instead of just going from dungeon to dungeon, I started to appreciate the game a lot more. I'd now say it's my second favourite Zelda game, to OoT of course. It won't give you anything unexpected, but it has a great atmosphere to it, and it's familiar without diverting off course like Wind Waker and Majora's Mask. Some people consider that a minus, although I like that it stuck closer to what I liked, rather than including gameplay elements that I felt largely detracted from the gameplay.
I'd say it's a game worth playing for any Zelda fan, although for the price it fetches these days, it really may not be worth it to many.