is it a good idea to start big projects with non dot com ?

Everybody has a great idea sometimes , nowadays i have one also ..i love to go with exact match domains . When i check for domain as you guess dot com of domain is already taken . Domain is controlled by one big domain investment company in us .

They are asking for 10 ,000 $ + price ..my latest offer for domain is just 3000$ . i m waiting for their response .

Now the question is , if you think your project is big .. Would you invest more on domain ? or start with avaible other new tlds .

Which way will you choose and why ?