I've really only watched a few anime series,but I'll contribute a bit. Keroro Gunsou- I got bored with it years ago, but it used to make me laugh and entertained me for many hours with the music. I loved Afro Sergeant! Hetalia- I find this anime to be really funny if you understand some of the historical references and aren't too offended by some of the stereotypes. This is anime is probably the least time consuming what with the 5 minute episodes and whatnot. I also find the music to be extremely catchy and (mostly) upbeat and you might find yourself to be singing along to the ending songs quite a few times. Both of these I think are on NetFlix right now.
Watch Big O if you ever have the oppertunity. Think Batman with a megazord. This is coming from a guy who generally doesn't watch Anime. Just be prepared to be sad that theres no real good way to get Big O toys for another few years if rumors are even true.
Cowboy Bebop Ghost in the Shell Legend of the Galactic Heroes (only online) Death Note The original macross series and macross plus original Gundam series These are great.
