Important shit

To install. Im formatting this OS soon and I'm wondering important things to install. I've got the basic stuff planned out, like CCleaner, FF, Defraggler, MSN, and other stuff, but thats about it. iTunes and VLC, too, but I still wonder what AV to get. Im thinking of ESET NOD32, but I wonder if there is better ones or other ones I should install too. ESET and Malwarebyrtes maybe?

Anyways, other important programs to install too. I wanna try and keep this drive clean as long as possible afterwords, considering now there is about 100-200 gigs on my HDD that I have no idea what it is. Don't suggest games though as I already have those.