Windows Vista 32bit
Although it is slightly more bloated than windows xp it does allow you to get work done quicker with new features like the instant file search and the ability to retrieve previous version of files. This is brilliant if you have a habit of saving over important data. The cost isn’t too bad at £60 – £115

Skype
Arguably the best free instant messenger, audio/video conferencing software.
http://www.skype.com/download

Windows Messenger
It comes bundled with windows and a lot of people use this as their main instant messenger software. So I use this for people that don’t have skype.
http://get.live.com/messenger/config

CutePDF Writer
Ever wanted to turn a document/image into a pdf? Now you can. This adds a virtual printer to your computer that will turn anything you give it into a pdf and save it on your computer.
http://www.cutepdf.com/products/CutePDF/writer.asp

Firefox 3
A very very fast and customizable web browser.
http://www.mozilla.com/en-US/firefox/all-beta.html

Opera
A fast web browser.
http://www.opera.com/download

WinMerge
Useful for comparing two or more text based files and highlighting the differences.
http://winmerge.org/downloads

UltraVNC
lThis can display the screen of another computer (via internet or network) on your own screen. This allows you to use your mouse and keyboard to control the other PC remotely. It means that you can work on a remote computer, as if you were sitting in front of it.
http://www.uvnc.com/download

VideoLAN
VLC media player is a highly portable multimedia player for various audio and video formats.
http://www.videolan.org/vlc

WinRAR
Compression software that can read/create both zip,gz,bz,7z and rar archives. It gives a very good rate of compression. The compression is usually better that the standard windows zip program but not as good as 7zip. A very cool feature is it’s ability to have a recovery record in the archive to protect against corruption. It costs €29,95.
http://www.rarsoft.com/download.htm

7-Zip
This creates very very compressed 7z archives but unfortunately can’t read or create any other types of archives.
http://www.7-zip.org/download.html

MWsnap
Brilliant for creating quick screen shots of part of or all of the screen and then saving them i na file format of your choice.
http://www.mirekw.com/winfreeware/mwsnap.html

Open Office
A free replacement for Microsoft Office.
http://download.openoffice.org

Folding@home
You want to cure cancer but aren’t a genius scientist? No problem! Just download and run this software. It will use idle processing time on your computer to do calculations for Stanford university in their quest to cure diseases related to protein misfolding.
http://folding.stanford.edu/English/Download

Synergy
This allows you to share a single mouse and keyboard across multiple computers.
http://sourceforge.net/project/showfiles.php?group_id=59275&release_id=406637

AVG
This is a virus scanner that’s free for home users. If you want to use it for professional systems then it costs £39.99.
http://free.grisoft.com/ww.download

Mozilla Thunderbird
A free open source email client.
http://www.mozilla.com/en-US/thunderbird