No pictures because I'm too lazy.
Mario
I like him enough. He is the Main character for who we owe the entire series' existence to. That said I don't play as him too often in most games.
Luigi
Probably my favorite Mario character. I almost always play as him in the Mario Spin-off games. I can't really explain WHY I play as Luigi the most clearly enough, but I just do. In Brawl/Project M, he's even one of my four mains.
Peach
Eh, I kinda dislike her most of the time. Because in a majority of the games she's in, she's either a bitch to play against in the Mario Spin-offs especially in Mario Party. Or she's always the damsel-in-distress. The only exceptions here are really Super Mario Bros. 2, Super Mario 3D World, and most of the Mario RPGs (Albeit I mostly saw the Paper Mario series regarding this. I haven't read everything of what Peach has done in the Mario & Luigi games. Though I know Peach was a party member in Super Mario RPG as well). She's not the worst Mario character by any means, but I wouldn't consider myself a fan of her.
Bowser
Even if most of the time he's always the villain at the end (For the exception of pretty much most of the RPGs even if Paper Mario 1 and Sticker Star had Bowser as the final boss). He's pretty cool. I can't wait to try him out in Smash 4 where he looks to be far better then he ever was in the series.
Toad
I kinda like him as the short sidekick to the Mario Bros. He's been a part of the series for as long as Peach and Bowser has. Also I really liked his voice in Mario Kart 64 (Though part of it might just because I found his scream funny. Still I liked his "YAHOO!" and "Yeah! Hahaha" better lines then most of what he's said ever since he got that raspy voice that started in Super Mario Sunshine, I believe. While recently it's gotten confusing on just who is "the" Toad with the fact we had the Blue Toad and now Captain Toad. Toad's a bit of a classic either way. And for pete's sake, Nintendo. Toad could be a a Smash Bros. character and not just be Peach's meatshield :V
Yoshi
Yoshi's alright. He's made some pretty weird noises in the past though (Just what was used exactly to make his voice in Mario Kart 64?
). He also seems to always be kind of the underdog in Mario Party. Because even in most of the Let's Plays I've watched the person who's usually the underdog that wins the least amount of time plays as Yoshi. Like NintendoCapriSun from The Runaway Guys, and Clel from Mario Party TV. So in some ways, at least in Mario Party. Yoshi is like the Underdog who almost never wins, and when he does win it's a little more satisfying.
Donkey Kong
While I don't play his games alot. I know he has really big importance to Mario as of course he debuted with Mario. (Though some say Cranky is actually the old Donkey Kong and the Donkey Kong now is something else entirely... but wouldn't that make Mario really old then?). Kinda wish he'd be playable in the Mario Party series again though. Just have Rosalina be the one who gets the opposite of Bowser's spaces. I think it'd make much more sense. Not that Donkey Kong being playable would be enough to convince me to buy any Mario Party with that
car...
Wario
He's fun to watch. I enjoy the addicting WarioWare series. And it's occasionally fun to screw around with him in any of the Mario Spin-offs. His Tuba + Accordion theme was just too perfect for him in Mario Strikers Charged.
Daisy
Er... she's kinda... my least favorite of the Mario Princesses. And considering I said I disliked Peach, that's saying something. She only exists because they needed a counterpart for Peach in the Spin-Off games, and "supposedly" give Luigi a girlfriend (Though the only things that have really hinted at any relationship between them is a line in Mario Power Tennis and the Statues in Daisy related course in Mario Kart Wii). And other then being more Tomboyish, she doesn't really provide anything that Peach doesn't already do. And despite Daisy having technically existed since 1989. Rosalina's earned more merit, and become much more likable in just 7 years then Daisy has in all 25 years of her existence.
Waluigi
I actually really, really like Waluigi. He used to be just a bit of a filler character, but I think Nintendo has provided lots more personality to him in some of more recent spin-offs. His quirky appearances in the Brawl in the Family comic and some of the Let's Plays have also giving me some Waluigi related laughs. If any of guys have seen the Runaway Guys play Fortune Steet, remember "Waluigi's Bridal Boutique"? But I think he shines the best in the Mario Striker games. If Waluigi is ever playable in the Smash series, that crotch chop NEEDS to be a taunt or at least a victory animation. It's just perfect.
Bowser Jr.
He's alright. Don't really care about him too much though
Birdo
Don't care whatsoever.
Rosalina
My favorite of the Mario Princesses. And not just because she's better then Peach because I don't dislike her as much. I actually do really like Rosalina. The recent promotion she's gotten was pretty sudden. But otherwise, it's cool to see a new and generally well-liked character get into some good spotlight. Some would argue too much, especially with the fact she got into Smash Bros. somehow. But nonetheless, I really welcome Rosalina. She'll be interesting to see how she does in Smash 4
Toadette
She's just a female version of Toad really. She's ok, and was cute in Thousand Year Door when she's telling Mario how to do upgrades. But otherwise I don't have any real strong feelings about her.
Baby Mario & Baby Luigi
I think of the babies they do have some worth in bringing in for the Spin-Offs since they actually do have some relevance to the games. The Yoshi ones anyway. Really I think most of the Baby Bros. I like the most is a stage in Double Dash called Baby Park. That stage was insane!
Kamek
I kind like him in the way that if Yoshi were to ever get a 2nd character. I'd hope it'd be him. As he's pretty much the closest to a main antagonist of the Yoshi games. It's a bit of a pipe dream. In other games he's just a character that either creates the bosses or makes the bosses harder. Don't really care about him when he's basically just the lackey for Bowser.
Rest of the Babies, the Metal version characters, and the Koopalings
I don't care
They could literally add Baby Metal Koopalina (Metal Baby Rosalina turned into a Koopaling) as a character to Mario Kart. And I still would not give a damn.
...Ok to be fair I'd be laughing my ass off if that happened. But otherwise, yeah.
