Cormac
It depends on what you are trying to achieve. If, like so many failed .com's, you don't have a proper business model behind you you won't last.
It may seem like a harsh, cold business approach, but I've seen a lot of really good ideas go belly up due to lack of forethought. Look at the list of deleted .ie domains and you will see plenty of failed web businesses.
A developer can help you with costings in terms of getting it all setup, but if you haven't got the other parts of it worked out it can hurt later. If you want to sell advertising, for example, you may need to get yourself VAT registered..
Just my two cents
Michele - who just came from an Enterprise Board "do"