The Best Software To Keep Your Computer Safe

What is the best software suite to use on your computer. There are many many different programs out there claiming to be the best for your computer. I have in the past used cover CDs to try out new software or to get what the "experts" called the "must have" program or software. This is great as it lets you try before you buy but it also can be damaging as you delete the programs off your computer you don't want to keep. Little bits and pieces of those deleted programs are left behind they start weighing on your systems resources. There are delete programs out there many many of them. Let me know if you have found any great piece of software you just cannot do without and would just die if it was removed.