Let's talk about perspectives for sprites and how can be implemented. 

Arereal. Used in Final Fantasy.

32x20 (I don't know the name) Double Dragon.

Side. Super Mario Bros.

Isometric. Ages of empires.

Orthogonal. This one is very frustating for me. I found it here but I couldn't find a tutorial or game using it, I tried many times but I couldn't fix it.

So...

Which are you using? Which are your favorites? Which are the avantages and disavantages of each one?

Talk to me. =)