my favorite is spider at http://sourceforge.net/projects/eraser/ ; just don't forget to say OK at the end and reboot. Spider is FREE

This erases browsing info in the registry and all over. So far, I haven't been able to find the info with other index.dat viewer tools once spider is run.

You can then erase all "blank" space on your HDD with a multiple-writerover eraser and that should take care of recovery.