I bet you will need at least one of these in your life!

[Da Fish]

Some of the best free/open source bits of software available. I'm willing to bet that you will need at least one!
http://news.bbc.co.uk/1/hi/programmes/click_online/7404655.stm

[Fixxxer]

I, like many, use Zone Alarm. So I already have one of them.

[Ronin]

I use LogMeIn (the free one) for accessing my work PC from home. I also use
the Delicious Library on our Macs to keep an inventory of our DVDs, CDs and
other stuff with barcodes.

Pretty good list, there.

[Aramis]

Already use MediaMonkey to organize and tag all my music. Great for pulling album art and proper tagging off of Amazon, so the lazy like me don't have to do it. LogMeIn would be fantastic if my work (and most businesses) didn't block the website you have to access it from.

Audacity, AVG, Picasa and Paint.net all find use on my PC as well. I suggest those if you have need of them.

[Wolfsong]

I use VLC and Skype.

Skype was the "official" communication tool at Grin, besides e-mail of course.