GTO is one of the classics of anime – it has a great main character, excellent supporting cast, strong storylines and on top of that it's absolutely hilarious. Based on the manga of the same name, the anime actually manages to do something that's very seldom done–improve on the source. It deepens the material and often resolutions have a deeper emotional impact than in the manga.
It's funny, unique and definitely feel-good. Eikichi (Great Teacher) Onizuka is something of a lech and a pervert, but he (almost!) always has good intentions and you can't help but like him. His ecchi-ness also takes the edge off of a series that could otherwise sink into tacky sentimentality.
This first volume is good, but believe me when I say it just keeps getting better from here on out. GTO – a hero for the ages ^^