I used to use Foxit, but it became rather bloated, and I remember it trying to foist other software on me. I now use PDF-XChange Viewer:
Tracker Software Products :: Product
It starts faster than Foxit and is also available in a "Portable" version which doesn't need installing, and can be run from a memory stick.
Or if you want a really basic tool try Sumatra:
Free PDF Reader - Sumatra PDF Again, available as installed or portable.