My only comment with regards to Evil is something that WolfHere's post alludes to.
Whatever type of evil you choose, never plan a PC under the conception that you will be murdering other PCs. It may happen, sure, but don't start putting a hit-list together from the get go because it wont end pretty OOC.
Remember to respect the other players. Whilst you may enjoy playing a psychopathic serial killer, other players may not enjoy having their PCs killed.
Although that is not to say it doesn't make for some good roleplay if players are sensible and understanding. Back when I played a ranger, I ended up on a solo manhunt for just such a serial killer. It was some great roleplay, and even if my Elf had eventually been killed on his chase, I would've taken it on the chin, as it was one hell of a show.