People ask me for software recommendations a lot, so here ya go...
For Anti-Virus and Anti-Spyware: Webroot Antivirus with Antispyware and Firewall - All three in one product, it finds more of the garbage on your system than any other product I've tried, and the computer performance slowdown caused by it is less than other products since one program is performing all three functions. $39.95 for one computer, $49.95 for three.
For blogging: Windows Live Writer - Compose and edit blog posts on the computer instead of the web. Free.
For fun: Worldwide Telescope - Navigate the heavens in a Google Earth-esque manner. Free.
For web browsing: Opera browser - This is so much better than Firefox it isn't even funny. Many times faster, more secure, more stable, no memory leaks, and still free. For PC, Mac, Linux, others.