New Computer with Vista. What security programs do I need?

[mlpjd]

Hi there. I just got a new computer this weekend, and it runs Vista Home Premium. I have heard that there is a firewall and spyware software included with Vista, but not antivirus. Is this true? What programs do I NEED to run?

I have learned the hard way that running more than one security solution can seriously slow your system down.

I got some software free when I bought my computer. If I NEED to run additional things, which of these would you recommend (or please tell me if they are all crap):

PC-cillin Internet Security (says it includes AV, Spyware, Firewall, anti-phising and some network stuff (but I don't have a network)).

System Mechanic 7 Professional (says it cleans spyware, includes iolo AV, iolo firewall and some other stuff).

webroot Spy Sweeper

Registry Mechanic PC System Repair (by PC Tools Software)

Any advice is appreciated. I'm delaying getting on the internet with my new computer until I have my security set up figured out. Thanks!

Mary