hmm i like to use
spybot 1.3 - removing spyware
crapcleaner - to remove all cache temp and cookies from IE and firefox (good for making sure system maintanance)
firefox 1.0 - coz 98% of the spyware u are likley to get will come through using IE6(activeX, trojans and secruity issues) although i will probley get bashed for saying that.
regsupreme - good for cleaning up old reg keys, nasty reg keys and inmproving system boot performance imho
kaspersky anti-virus - for obvious reasons, coz its the fastest most best anti-virus-anti-spyware detecter and remover out there IMO.
Windows xp sp2 firewall - idiot pr00f, love it, although Kerio 2.x.x is amazing
a tweaked system is allways good, diabling a couple of services u jst will never need ever... improves performance and stability. also download java 5 now!
it is very important to install java coz it blocks some holes and fix some issues with IE that can be very ghey in the long run.
also IP and tracing secruity, go to these sites and read all information, especially if u do p2p, IP, HOSTS and privicavy is jst as important as spyware and virus prevention.
www.bluetack.co.ukwww.methlabs.org/methlabswww.againsttcpa.comIP hosts Blackliststhat should do it......or jst use mandrakelinux 10.1