Agree with cduffy. If they are offering you "car" or "downpayment on a small house" amounts, then you may wish to consider going it alone. But if they are offering you F U money, then think very hard about it. Many best technologies don't succeed, and almost as often, the founders donot get much of it because of dilution or getting forced out by the board or any other number of reasons. If you are looking at over $1M or so going to you, then think very hard about passing it up. Even if the money is less, having experience making and selling a company is a huge gold star to any VC or angel investor for your next company.
By the way, if you are really serious, get better advice than /. Talk to VCs, your clients and your advisors or mentors.