This is an interesting issue. After you finish re-installing your chosen operating system (whatever it might be), you usually address your top, absolutely most critical, needs first. You can worry about the applications you only use every now and then later. So, what is my top 5 list? The following is in no particular order.
1. Google Chrome [ Cost: free ]
Typically, while I am writing code, my main testing browser is Firefox (because of firebug) but for getting things done, I use chrome. It is fast, easy to use, and heavily customizable.
2. Microsoft Security Essentials [ Cost: free ]
Computer security is important. For years, I used a version of McAfee that UW-Milwaukee offered (my former employer). I had used it so long (since high school), that I learned to trust nothing else. After using Microsoft Security Essentials for a few months, I can confidently say that I will not be going back to using McAfee.
3. VLC Media Player [ Cost: free ]
VLC is a great little media player. It will essentially play any media file. I use it for both video and audio. It is the only media player I use. The supported codecs include (but aren’t limited to) Real Video, WMV, H.264, DIVX, and Quicktime. It’s pure awesomeness.
4. 7-zip [ Cost: free ]
7-zip is a file archiver that is much like VLC, in that it will open almost anything. It will even open things (like ISO) that VLC will open. It’s great to have around when you need to open the odd RAR or ZIP file.
5. Sublime Text 2 [ Cost: $59, free unlimited trial ]
Sublime Text 2 has easily become my new favorite coding environment. It is expandable, light-weight, and clean. I use it for just about everything. I don’t care what language you code in. You should check it out. It was an easy decision to add it to this list.
These are by no means the only applications that I have running on my windows computers, but they are the top-5 first items I install on each of my windows computers. I couldn’t live without them.