Fmonster, it sounds like you were on a dreamhost account or something similar??? they throttle cpu usage and their TOS specify they can shut you down for using too much resource.....heaven forbid you actually use the service they are supposed to be providing to you
A quality host will work with you to ensure you are running your scripts optimally and to upgrade your hardware when it comes time that you need to upgrade. FYI, I have quite a few clients that run multiple blogs (including me) and have no server load issues at all.
cheers,
Luke