Software    

Recommended Freeware

Defrag:
Remember to defrag regularly.
Pagedefrag - defrags the swapfile, small program, not a resource hog.

Anti-Virus
AVG Anti-virus - reliable with auto updates (can slow the system a bit)
Avast Anti-virus - with auto updates, doesn't hog resources much.

Anti Rootkit
What's a rootkit? Another breed of malice that successfully hides trojans from anti-virus software.
AVG Anti-Rootkit

Registry Cleaner:
Clean entries that point to nowhere.
Easy Cleaner

Startup Inspector:
What's running in the background?  View it all, and disable what isn't necessary.
Startup Inspector

recommended Security Plugins for Firefox

Adblock
Ghostery - blocks and confuses tracking cookies.
Https Everywhere

Visit Mozilla.com for these and other free plugins.

Recommended Purchased Software

Casper allows you to take a snapshot of your entire hard drive and move it onto an external drive for backup. (C_Language)

Ghost is another program that will back up all files without system files. (Valkyrie)

All kinds of software

OpenCPN - Marine Chart Plotter Navigator. Open Source (free)

Giveaway of the Day - Every day they give away a different program that otherwise would have to be bought.  That's right, free, no catch.  
Tucows - Paid programs and freeware.

No Nags - All freeware that's been pre-screened.  An excellent site.

CNet/Download - Freeware, shareware, and paid programs.

Source Forge - Everything is Open Source (free)

Brothersoft - Lots of helpful, free programs.

Mozilla Firefox - A much better browser. Open Source (free)