My philosophy is to wait to buy accessories so as to discourage and prevent GAS. Yes, accessories may cost more than the camera - all the more reason to not buy them unless you need (or really want) specific ones.
I agree! It is easy to get caught up in a buying frenzy but one often doesn't really know what accessories he really needs and will use until after using a camera (or anything else) for a little while.
The prudent person will wait to buy accessories so that he doesn't waste money on things he will never use.