ya Fairy Tail is NOT made by Eichiro Oda of One Piece, it's done by Hiro Mashima of Rave Master Similar style, mediocre quality, and decent action i guess. very light hearted.
Claymore is serious, at almost all times it's serious, it's gory, it's actiony, it's serious. it may have a naked woman but she'll either be killing or being killed.
Death Note is just a straight shounen anime except instead of fist fighting it's mind fighting, that's it, and it even had an opponent show up after one of them were defeated.
Ghost in the SHell on the other hand is all philosophy and politics, it CAN be slow or uninteresting for a little bit but overall it's a fantastic series, but yes you should see the original movie first before going into this.
Fruits Basket is pretty good in general, it's actually funny on most of it's attempts at being so. But it isn't serious til the end where it was more abrupt than thought out.
Gantz is fucking stupid but all blood, tits and explosions, like ELfen Lied except Elfen had some substance under it
Black Lagoon is badass but unbelievable and can get dull after a bit
Samurai Champloo is fantastic, especially if you liked Bebop, and your thought process on "japanese writers" making women ecchi all the time is stupid otherwise ALL anime out there including Pokemon would have it, and ecchi is only a small part of anime anyway. (although growing substantionally)
WHoever recommended Gungrave gtfo, Gungrave wants to be a modern day Berserk with no action, no sense and 90% boring, but high quality boring it is.
I will second Baccano! in every way, as it's AMAZING, and Darker than BLACK is pretty sweet too (some of the best action scenes in a long time)
tell Bubbles to shove Vampire Knight up his ass because it's not very good (not terrible) at all
and Gundam Zeta is great, Gundam ZZ isn't as great but still good. Macross Frontier was actually pretty good, but still one of the worst of the Macross series (but they're almost all great)
and whoever asked if Clannad was good the answer is YES, go watch it