I think Dani mentioned that you always want to have a dot com website address. Why does it matter if it's .com, .net, .ws?
Suppose you saw an advertisement for CoolCompany and you want to check out their webpage. Wouldn't you open a web browser and instinctively type www.coolcompany.com ?
Let's take a real life example. Suppose you wanted to buy a Sony tv but wanted to investigate it first. Wouldn't you type in www.sony.com even if you had never been to Sony's site before?
Having a .com extension just makes company branding a whole lot easier. If it was sony.ws, then Sony would need to specifically market "Sony.ws" on everything. And even so, a handful of their prospective customers, would still end up at Sony.com.
But they don't have Sony.ws ... they have Sony.com ... so they only need to market the part that matters - the company name - the brand name - Sony.
Also, especially in the technology industry, or for a site like DaniWeb, many web-saavy people realize that certain domain extensions such as .tk, etc. can be ordered for free or minimal cost. Therefore, if you're planning on starting up anything other than a personal site with such a domain extension, it may come off as cheesy.