As nice as the idea sounds, having an all in one sort of program, they tend to be less effective than a group of separate programs. Trying to be everything to everyone on a shoestring budget is never going to work out well.
There are a few good free AV programs, such as AVG Free and Avast. There's also the open source ClamAV (not entirely sure on the name) though I can't say one way or the other how effective it is having never used it.
On the malware front, AdAware, Ewido, and Spybot will likely take care of the bulk of things. Not using Internet Explorer will go a long ways on the prevention front as well. You can turn off scripting and ActiveX for IE and make it pretty safe, but you also kneecap most of its functionality. Firefox and Opera are both free, so I'd recommend using one of those.
It is also a good idea to have a firewall running. XP's firewall works fine, as does ZoneAlarm and all the rest. If you have a router with a firewall, that's sufficient and you don't need another.
And while far less common at the moment, it's only a matter of time before malware distributors turn their eyes towards Outlook and Outlook Express, and toss their lot in with the virus and worm authors, and spammers, who already have found the promised land that is Outlook and Outlook Express. By not using them, you lessen your odds of being hit by anything.
Combine all this with some basic internet common sense, like not opening strange email attachments, not just clicking "Yes" or "OK" to every dialog box that pops up in front of your face, never responding to spam... You shouldn't find a lot of need for an AV program or malware remover, though they are good to keep around just in case.