 If you liked Yuu☆Yuu☆Hakusho |  ...then you might like Shonan Junai Gumi! |
If you enjoyed YYH for the awesome fights and Kuwabara and Yuusuke being dumb yet charismatic thugs, and if you don't mind a fair bit of crass humor, then you will probably like Shonan Junai Gumi. SJG is a prequel to Great Teacher Onizuka and covers the main character Onizuka's days as part of the delinquent duo Onibaku. It's got great humor and some badass fights, and shows Onizuka and Ryuuji both kicking ass and getting their ass kicked.