Kazuma Kuwabara of Yu Yu Hakusho because the guy never says "I quit". You can count on him giving everything he has in a fight because his code of honor will allow nothing less. Besides, he seems like a nice enough guy to hang out with after the scuffles are over. I'm not too interested in "planet destroyers" but I like a guy I can trust in a good old fashioned street brawl.
"Twilight" Sukuza of Outlaw Star. She's strong and dependable in a fight but also interesting enough to be around in quieter moments. Not to mention she's pretty easy on the eyes and I like her wry sense of humor.
I would love to have Sebastian at my side in battle. Not just because I *cough* love him *cough* but he's an awesome fighter. He can't die, and I can honestly say I don't know any other man who uses silverware as a weapon ^^ He spears people in the head with deadly accuracy and has awesoe skills, folks!
Mafuyu Oribe from Seikon no Qwaser because she would give me a reason to keep on fighting, and if I ever got dehydrated, she has her soma (breast milk, for those that dont watch the show) to keep me going.