With all the tools one is required to run/install these days they need to quit shipping computers with just 256/512MB of ram. All the AV and Spyware software usually run in real time with their associated 1-25 MB service. Talk about eating up system resources. I know people who refuse to run AV etc just because of that factor. Maybe development needs to shift to lighten up on the system load or take in to account the fact that most people are using more than one product for protection. This can be done by event triggering, have a light client monitoring just events then when an event is triggered it temporarily loads the neccessary additional resource hog. Just an idea.

::edit::
I have roughly 45MB worth of process/services running right now that are dedicated to AV/Spyware. I cannot imagine what it would be like if I had a personal firewall running too. Thankful that our company's standard desktop configuration comes with 1.5 GB of RAM.