I'll watch anything, as long as it is good. When I was younger, I would've considered shojo manga/anime such as Fushigi Yugi and Marmalade Boy as a guilty pleasure.
Of the old mecha anime, Mazinger Z/Tranzor Z, SDF Macross stand out for me.
For 90's, Gundam 0083:Stardust Memory, Nadesico...