Hakan, cause he looked fun to play from the videos I saw before SSFIV came out and when I did finally get the SSFIV and played Hakan he was indeed fun to play. He also has a 360 command grab (I mained Gief in vanilla and I still play Gief today.), well two of em if you want to be technical. I also like the idea that he has to be oiled to be good lol, guess I just like gimmicks.
I mained Cammy because she was nimble and difficult to play (but easy on the eye–although if I was picking solely on sex appeal i’d choose any of the other female cast before Cammy, and her faux-british accent bugs me and her japanese actress sounds like gibberish). Also watching Allen vs. Allen??? and Aulord vs. Sanford videos sealed the deal. I think it was the hooligan grabbing hooligan in the air that did it for me. Pity only mirror matches look like that, although grabbing the shotos out of a tatsu or whiffed dp with it comes close. 
In every other game it was Ryu because of his character.
In this game its Ibuki because she’s a ninja and from 3s.
Well…Vega (Claw) because he’s pretty, I’ve always gone for androgynous men just because I love the eye candy <3. That an he just feels so unique compared to a lot of the other characters, He also yodels, this is instant win for me.
M. Bison (Dictator). I love his personality, this personality of “BUUUUURN!” with every sentence that comes out of his mouth (At least with some character specific winquotes…plus in his Alt.1 with the ripped up clothes he’s damn sexy.
Other than that, I just love being able to go rushdown with a character and have a lot of fun with him. I Alt-ed him in vanilla and continued to do so in Super so it’ll stay that way with him and Vega being my main until they’re no longer in a game.
I think him and Vega contrast eachother really well in my playstyle, so I went for them (And my other half found Vega insanely frustrating and I love getting on people’s nerves).
Ibuki. I like fast gameplay, plus she’s a damn ninja.
so you use Vega and… Vega?
I currently main Dudley and I’m sticking to him, but let me go down the long list of people I actually mained in SSFIV.
DJ - Was my highest in bp for awhile. Before the game came out i decided on him because he is just one of the coolest characters. Everything about him. He has one of my favorite quotes every ripped from Cool Runnings, haha. But I strayed from him recently because he’s really boring
Cody - Good friend of mine’s alternate is Guy. He’s the only good online Guy I’ve seen and we were a team. But I was never good with Cody so i dropped him
Ryu - Same friend also used Ken sometimes, so when we played team battle I’d use Ryu. Plus doing his trials were cool and I’d thought if I can replicate some of that stuff.
Guile - Everyone’s hero. Tried him out in trials, had some crazy shit. Found that I could do his links very easily. I liked playing him because i found i was really hanging with very good players online. But I gave up on him because he’s still pretty boring.
Makoto & Ibuki - I found nice set-ups (makoto her command grabs, ibuki her target combos) and I felt I could take them online and do work. But the characters themselves aren’t very good and the bad matchups I had were all the time and very very bad.
Hakan - Seemed like a funny character. His trials opened my eyes and I was actually tearing up people online. But when he has bad matchups, they are BAD!!
Barlog - I mained him in vanilla so it easily transferred over. But Barlog is such a boring character sometimes. I had to let him go, he’s not exciting, and I believe him to be too good.
Fei Long - I think he’s going to be my alternate. Once i figured out the speed for some of his trials, i was hooked. I became pretty good with Fei, even beaten a lot of friends who I previously could never beat. But after spending time away from SSFIV, I realized that I lose my skill with Fei specifically if i don’t keep training with him. So now I’m not very good with him.
and finally Dudley - well I needed another character since Fei Long wasn’t cutting it. I remembered Dudley’s trials were easy and I beat em all like 5 times. I tested him out, learned some nice combos and set-ups. LOVE counter picking with the ultras. I have I think a unique style of Dudley. And I’ve had the most intense, crazy, amazing, and clutch matches with Dudley in the past few weeks than I’ve had since I’ve gotten SSFIV, and I play against some really good players too. So I’m going to keep workin on Dudley to get to like at least a small tournament level. Damn that’s a lot of shit i typed.
isnt c.lk into s.hp a 1 frame link?
I main Bison, I am using him because in vanilla I played Guile for about 3 months (mostly because I used to use him in World Warrior when I was a tike). I lost a lot, then I just randomly tried Bison and started winning even though I didn’t really know how to play him. I took that as a sign that the character suited my play style.
I main Sakura because I know how to play Sakura because when SF4 came out I decided to main Sakura(because I played her in mvc2 and cvs2)… Also she doesn’t talk shit to anyone. All her win quotes are friendly, I like that
I really like her normals too. They’re really straightforward and simple. Some other characters have “weird” normals, imo. Like goukens c.mk… wtf is that shit? Weird, that’s what…
Cammy, no matter what. Always Have, Always Will!!!
Sagat, because he is powerful and uses Muay Thai…
… that’s why I also use Adon, who also has a mean streak I like.
Because his combos looked awesome, that’s why I first started playing as him.
Gouken - Iv always had a thing for the old masters of an art / I like everything Gen stands for, but Gouken is more manageable.
Fei Long - I was and still kinda am a huge Narutard and I fell in love with Rock Lee which also made me open my eyes to Bruce Lee. So I love any character that embodies his fight style/ideas.
I use Vega because he is a rushdown character, and unlike Cammy, Ibuki, Viper, etc. he doesn’t need amazing execution to be effective.
Also I dabble in Fei Long if only cause his focus is sick and I love mashing focus because THAT IS A SMART THING TO DO
Adon, because hes the true king of Muay Thai
Fuerte because I was using Ramon in KoF.
Also, he cooks… and I am a cook… he’s funny.
Fuerte got a unique style of play that let everyone have a different style, which make him the hardest character to handle properly and also the hardest character to beat.
My second is… well… Dan…
started with Blanka/Sagat, but then to force me to learn better the game mechanics I switched to Cammy (character I knew nothing about), today I keep learning the different chars but Cammy is my tourney main.
Ryu
-Always been using him since I started
-Like his hadoukens
-Like his play style
Akuma
-Favorite SF character
-Love his combos
-Just started maining him recently, had been using Ryu most of the time (thought a change would be good)
-Looks badass
Juri
-Coolest new character in SSF4
-Like her quickness
-Her attitude
-Fun to use