I agree with Katie - go to a salon, even if you don't normally.
What colour is your hair naturally though? If it's quite dark, you'll have the never-ending hassle of touching up your roots every couple of weeks too, and if that's not done properly, it looks awful. If you're not prepared to go to a salon every time - and I don't suppose you are!! - I think you'll regret it...Why not get some professional advice? A colourist will have a chat with you, free, and you may decide on something you wouldn't have thought of before. :o)