It's hard to pick the best anime out of my collection, but I'd have to say that the top 2 would have to be Cowboy Bebop, because Bebop just has that style to it that makes it stand above the rest, and Rurouni Kenshin OVAs, because that OVA series pretty much blows away the competition. In but 4 episodes you get a broad view of Japan at that era and certain depth for the characters in such a short amount. The Irresponsible Captain Tylor and Ranma 1/2 come in a close third. The Irresponsible Captain Tylor, because I love the laid back attitude the captain portrays and the whole question to whether he's actually a genius or just a lucky idiot. Ranma 1/2 is just funny. Everyone I know, even the people that don't watch anime or criticize it as being kid's stuff cause it's animation thought Ranma 1/2 was funny, and actually kept watching it.
If you are reading this, you obviously have nothing better to do with your time.