According to research from the marvelous Influence at Work people you should make the first offer if what you want and what the other side wants is very different (e.g. you want a high price, they want a low price).
On the other hand if your views are compatible (e.g. we want to start very soon), then it’s not necessarily a good idea to make the first offer.
The blog post from which I took the quotes has been removed, but you can find the details (and more) in the the Small BIG by Cialdini and his colleagues.
