Mainly depends on your age and preferences.
If you think you're mature above watching the dbz/naruto/pokemon/yugioh level then I recommend watching:
Death Note - more mature
and definitely Tengen Toppa Gurren Lagann which suits everyone.
heres:
http://www.zomganime.com/tengen-topp...en-lagann.html
http://www.zomganime.com/death-note.html
welcome.