Never "decline". I say I consider the entire compensation package because I realize they are a startup and need to sweeten their offer with stock because they don't have the revenue to pay a market rate.

It's important to neg them a little when you guess what they will offer. Male them self consious about lowballing you without insulting them.

I actually am beginning to think that its weak to ask them to throw out a number. Why not state a deal that's 10% better than what you want? Are you really going to be heartbroken if you get more than you want?