I must admit that I have a soft spot for the underdog losers. This stems from the fact that I am an underdog loser myself (shock) and thus feel their pain. So it is always nice when an underdog looser turns out to secretly be awesome as it gives me hope enough to plow through another day.
This is why I love Dan Hibiki.
It is common knowledge, amongst 2d fight fans, that Dan was created as a big FUCK YOU to SNK. He was first depicted here
being killed by Sagat and normally it wouldn't have gone any further than that. But somehow he grew as a character, accessable by cheat, in Street Fighter Alpha. It was here that it became obvious that he was an insult character, the Wimp-Lo of the SF universe. His shitty gadoken

, his gale kick (gales being mild annoyances as opposed to the destructive force of a hurricane inspired kick), his constant crying and taunting, all of this was directed at SNK as a comment on their product. He also wears pink to a fight, nobody does that unless they are really, really good or really, really bad.
But he was a great character to use and he has only gotten better.
His moves were not great, but they worked as a great lure, people suspected crap and would fight like they were safe for harm, that's when Dan layed down the big hurt. His standing hard kick in Alpha 3 is great too, works well as an anti air, it's fast and it even has a little advance creep that gives it a deceptive reach. He was a good fighter.
But beyond that is the character of Dan, his constant optimism in the face of sucking so hard is like a "Hang in there baby" poster with a gi on. He is like a motivator for the other fighters, as in this hypothetical situation...
Ryu: Hey Ken, there is another big tournament being organized by Bison, wanna go?
Ken: No, in the last tournament Bison mindraped me, I think I'll stay here where it's safe and get my hair done.
Ryu: So you're too scared to go?
Ken: I wouldn't put it that way exactly I jus-
Ryu: Dan's going.
Ken: ...
Ken: Shit. Alright, lemme get my stuff.
And so on.
Also his love of showing off and taunting reminds us of what the martial arts are really about., looking cool. It is in this vein that he works great as an insult to opponents, the role he was born for. Beat someone down with the joke character and you shit on their skills, nail a SUPER TAUNT and they may as well gut themselves over the machine 'cause their pride 'aint comin' back.
His story is a sad one, his father was killed by Sagat (a fate that Dan shares) and his ending in SFA3 is somewhat meloncholy as well, but knowing what awaits him makes his determination and optimism all the more inspiring. He may be a laughing stock, but he is one of the most sympathetic and deep characters the SF universe has ever created. He might not have the skills of Ryu, but I challenge Ryu to demonstrate anything near the courage and heroism that Dan does. Up yours Ryu, you smug shit.
I consider myself a diciple of his Saikyo style. Long live Dan Hibiki, the strongest fighter ever, may your name be etched into the tablet of history!