My favorites would have to be Luigi and Mewtwo. I also liked Pikachu, Lucario, and Meta Knight.

I like playing as Ike even though some people say he is overpowered, his move set is awesome and he is extremely powerful. Granted he might be kind of slow because of his sword but he is still very strong and his final smash is awesome. I just wish he had a more effective way of recovering and getting back up from being knocked out because the move I use with him spinning and slashing his sword down gets me Ko'd a lot, but he is still a good character in my opinion. 

Other characters I like using:

marth: he is fast as heck and he can rack up a ton of great combos to do a lot of damage

link: he is just cool and has a variety of ways to give damage, from arrows and bombs to his chain ball thing, he is just awesome. I know toon link is better because he is faster, but regular link looks so much cooler.

sonic : his final smash is amazingly strong, not to mention he is super fast

meta knight: I don't even need to explain why he is a good character.

these are all of my favorite super smash bros characters to use. Good question by the way. 

Here's where all the so called "Pro Players" give all the hate. Say he's Garbage all you want, it doesn't change the fact that he's the man. MY MAN KING DDD!!! Bubblegum Pink costume all the way. Any other color and the magic just isn't there. Why do I like him? Well he's just overall awesome, and that's a lot coming from someone who has a lot of trouble using slow characters. Bowser? Get him outa here. Charizard? PFF too hard to work with. DDD? Well we can say I've seen a lot of win screens with DDD up front.

Outside of my man up there, I enjoy the quick characters like Fox, Falco, and Falcon as well as the characters that are never chosen for good reaosn like Ness and Peach. Lucas is nice too along with Ike and Pit but DDD will always be the greatest.

I like Pit as my primary, and Zelda/Sheik for my secondary. I mainly use Sheik, unless I'm playing with someone new to the game or not that great at it. Using Zelda gives me a slight handicap that makes it easier for them to master the basics, but once they have those down... I turn to Sheik and pound them.

 well i would have to say Roy, cause hes the strongest of the brothers, and is boss looking

My favorite Smash Bros character is Kirby. I am very used to using him, and I really like his moves. I also like playing as Link, Marth, Roy, Ike, and Pit.

My favourite SSB character would definitely be Samus. Her move set is great. The up + B has saved me many times. i've never played melee, but Link was really good to me in Brawl.

My favorites are Samus and Meta-knight. Samus's gun is killer (as well as her special smash). I've won many brawls with friends as Samus and play using her on all normal levels. If I know that I'm playing on a rigged level of a friend, I play as meta-knight. His flying abilities will stop me from hitting spikes for a few seconds if the whole map is based on spikes and escape falling off of the edge in most cases.

Sheik all the way.

I know I've already posted in this thread, but opinions change.

In SSB64: I usually use Fox or Pikachu. They're pretty easy to control and they are sweet at combos.
In SSBM: In Melee, my best characters are Ness (combos), Pikachu (fighting), Ice Climbers (all-round), and Sheik (chain-grabbing).
In SSBB: In Brawl, I always like to beat the crap out of everybody with Lucas. His Up-Smash is the second strongest in the game. He also has PK Thunder, the cheapest move in SSB history (next to Kirby's undodgeable suicide bombing in SSBM).

Sheik, fast, strong, high jumps, and skin tight clothing. Plus, people always underestimate her.

My favorite characters are Roy, Doctor Mario, and Snake.

I like Roy and Doc because they are powerful and I like their designs. I like snake for the Codec Calls and he is character who plays around with traps.

I've Only Played the One on the Wii. But out of all the characters there wich in my oppinion are a Lot: My All time NR.1 Favorite would have to Be Wolf Sure his fighting style is Similiar to Fox and Falco, but he just looks alot cooler then . Robo is also fun to play with once you have his moves Mastered. And the jetpack in his wheels has saved My life plenty of times. Sonic is fun, but his speed has at times backfired and caused me to kill myself xd

My favorite Super Smash Brothers character has to be Sonic the Hedgehog because he is fast, semi-powerful, and has a really high assist jump to get back to fighting if you get knocked off the arena.

I love using Samus because her arm cannon is fun to charge up and hit people with.