This is more reason to research the company's salaries up front. If they were planning to lowball you and you put out a high number, it may help you, but if you don't know anything about the company, it may be more beneficial to let them make the first move (unless you have multiple options open and are willing to say a high number).
the problem is that salaries aren't uniform for all companies.
so if you go by glassdoor, you'll see that some engineers make $40K/yr, while others make $150K/yr in the same area.
If you go by listed salaries on job descriptoins, once again on monster.com you might see jobs posted at $100-150K/yr...while others, for pretty much the same exact requirement list/job description you'll see $50K
The good thing though, is that if you ask for more than they can afford, they'll almost always tell you their real number. So just ask for 1/3 more, i.e. if you want 90K, ask for $120K, then watch them come up with a 100-110K counter offer....and who knows, you might just get that $120K
