I'm reading/I've read :
- Ubelblatt, not bad, but it's pretty serious. I mean, that's not a 'casual' manga, some manga you can read one tome then drop it.
- Rave Master, completely crazy. Basical shônen with a lot of fun.
- Fairy Tail, same as Rave Master (same author) but without scenario. Fun and refreshing if you're looking for a time killer.
- Jackals, some violent manga about bounty hunters. There are only 7 tomes, and the scenario is pretty simple. Not so bad, but not that good either.
- Island, a korean manga (manhwa). The first (and only) manhwa I've read. Very good scenario, but it seems that the author did not finish the manhwa.
- Tokkô, by GTO's creator. Nice manga but again, the author dropped it after 3 tomes.
- Get Backers, pretty simple at the beginning, but it hides a deep story. One of my favourite.
Then some classicals like Bleach, Naruto, Rurôni Kenshin, Gunnm, GTO, Hikaru no Go, Chobits,...