It's the F-word that always gets people's attention. And whether it's to enhance your office systems or just keep you busy during down time, the Web, it would seem, has the answer to it all. The best part: A bulk of this veritable treasure trove is 'Free'. But how do you decide what will stay true and serve its purpose? And how do you avoid something that will crash and burn, taking your expensive system along with it? Luckily you don't have to. We give you a list of the must-have software and the best services on the Internet.