Oooh...well, it's actually been a while since I've read a manga (mainly because I'm REALLY picky), but I really, really liked Alice 19th...however, it was moreso a shoujo (girl's comic)...so, it depends on if you're into that kind of thing. I mean, it wasn't like Sailor Moon or Peach Girl, it was just a bit on the girlish side...
There's also Clover, which is a short series by CLAMP...it's kind of confusing the first time around, so if you didn't get it, read it again.
Um...hmm, I think that's about it...I haven't been manga browsing in a while, so if I read any new good ones, I'll be sure to let you know about them...