For me it's not a question of bandwidth or space. It's all about the CPU usage. Most of my pages are dynamically rendered. Right now my hosting setup is this.
1x Dedicated (blackhat scripts that bring complaints)
2x Shared hosting accounts (blackhat)
1x Reseller hosting (grayhat)
1x Dedicated (ppc)
1x VPS (mysql database server to take the load off the 2x shared hosting accounts)
I wish I could move the blackhat onto a VPS or dedi(I'm on my "final warning" with the hosting company) but I don't like people being able to find all my sites with a simple lookup. So I'm kinda boned into shared hosting.