I admire some of the stylization in Bleach and Naruto, but the deficiency in pacing of just about every anime I've ever tried to watch has never failed to exceed the limits of my patience. I happened to have finished Afro Samurai - which, mind you, is only five episodes long - and found it irritating and bizarre, failing almost across the board to live up to the promise of its opening minutes.
No list of all time best/most groundbreaking anime is complete without the presence of Akira and Neon Genesis Evangelion. If you haven't yet watched them, do it. Also, try Grave of the Fireflies; it will make you cry big man tears for days after having seen it, and it's regarded by many critics and film buffs as one of the greatest war films of all time. Also, Monster (which does a good job of avoiding all of the annoying/bizarre lighthearted anime humour and is just plain awesome) and Elfen Lied (refer to the part about you crying like a big chubby woman). For some really old stuff, also try Space Battleship Yamata and Space Runaway Ideon. Gundam and Cowboy Bebop are also very awesome.
If you already have a negative preconception regarding anime I'd recommend avoiding all of the mindless shonen action anime (Dragonball, One Piece etc.) or the horrifying comedy series (such as Gintama) as it will probably just confirm your initial expectations.
Spoiler:
if you want nice sexy time I would also recommend Moonlight Lady... 😐