I own Kaspersky. I install it on every PC that I repair and it protects all of my home computers.
Because it is the best internet security suite on the market. Novice users can install it without fear, as the program defaults into an "auto mode" that will decide all the tricky questions itself, whereas power users can easily take full control of the suite and it's advanced detection techniques.
Version 2009 has a HIPS system (not the type that you shake at a party), but this HIPS system controls the applications on your computer and can intelligently decide what "safe" programs are (like microsoft word and others) and what "dangerous" programs are, and make sure that they do not have a chance to damage your computer. Virtual keyboard is useful for typing in passwords and usernames into bank logins to minimise the risk of keyloggers and antispam is accurate and has regular updates, like the virus signatures.
The scans are fast, the support is good, the detection rates are the best in it's class.