Again, Hajime no Ippo is a great watch. It's about a wimpy kid who turns into a pro-boxer. Watch him rise up from lonely rookie to hardened national champion. The original series is 70+ episodes long and has two OVA's (which chronicle two matches right after the original). There is a second season currently running, and it was worth the wait. There's a reason why the manga of this is 850 chapters strong and shows no sign of ending (it's that good).
Great Teacher Onizuka is one of my favorite animes of all time. Great comedy about a pervy ex-biker gang leader who suddenly wanted direction in his life. His answer: be a teacher, so that he can have a 16-year old wife by the time he's 40. He's also semi indestructible. He saves a student from jumping from the top of the school twice and shrugs the impact off. The end to this was made up. So if you want to see the "true end", read the manga at the point after the Beach Episode (it's really worth it).