I haven't seen many animes, I am more the manga person (or better to say original source person) but here are some top picks from both sides from me.
Anime:
-Armitage III, very nice little sci-fi anime
-Agent Aika, besides the fanservice and all I really love the animation style, the action, most of the characters and so on
-Cowboy Bebop, I guess I don´t need to explain this masterpiece
-Neon Genesis Evangelion, I should rewatch it one day but I am still waiting for the next movie of the new series
I guess I nearly counted up every anime I´ve genuinely watched and would recommend.
Mangas:
-Elfen Lied, I read it nearly once every year, discard the anime and only read the manga, that's the true stuff.
-Franken Fran, I am no fan of the horror genre, but if there would be more like this I would consume horror ONLY
-Oretama, a bit on the perverted site but a really nice and well-made manga with very likable characters, good drawing style, and nice character development.
-Dragonball, it´s much faster and smoother than the anime, no filler, and it´s easy to consume the whole series in a weekend instead of in 300 hours, also you can see how Akira Toriyama started to don´t give a damn anymore at about the cyborg saga
-Urusei Yatsura, first long term work of Rumiko Takahashi, a masterpiece for me, especially the ending was so amazing. If it wouldn´t be that long I would read it more often.
-Death Note, also very well known, I really enjoyed how far they planned all and thought about their plans and tried to predict the others, it was very fascinating.
-Rave Master, very nice shonen manga, you can see much development on the drawings later, it becomes a little weak in the middle, but the pace catches on again at later part of the middle.
-Mahou Sensei Negima, I always describe it as a mix of Dragonball and Harry Potter, it is SO AMAZING, I LOVE EVERY FIGHT in it. It´s so hard to find such a vast amount of characters that are nearly all unique and take part in some sort or another in the story. I was so disappointed in the anime (except the fight of Negi and Eva in the scroll Jack Rackhan gave them when I saw Eva animated it was like an orgasm for my brain). I hope the sequel becomes as good as this one.
I guess that´s all for now, I surely forgot some things, I read and saw Hellsing, it was good too but I think in the end it slacks off too much. But I love the very early drawing style in the first chapters of the manga.
Sadly there are many mangas I want to continue reading but just find no time, like air gear was awesome too but I just found no time ever to finish it.
There are many I still need to watch, I am a big fan of old Animation styles and want to watch much more of the 70s, 80s and 90s anime, especially fantasy and sci-fi. It was just so beautifully made back then.