Im giving FF3 another go as theres been an update to see if the CPU leak gets any better. On my travels I spotted this add on
https://addons.mozilla.org/en-US/firefox/addon/5721
Its a visual bookmark thingy so when you open a new tab instead of it being blank it populates the screen with thumbnails or a custom pic for your bookmarks like this
You can set the size of the thumbnail, the size of the grid for more or less bookmarks, the background colour and also a custom pic of your own rather than the screenshot which it generates. On the Mac version theres a magnifying glass next to the custom image field which if you click takes you to a site where there might be a custom pic uploaded already if its a popular site like Demonoid or Hotmail which you can download for free.
You set the bookmarks by right clicking the empty boxes and go from there. You can set them to open in a new tab, current tab or new window individually.