We have also used Foxit and it's fine, but actually we are set up with CutePDF.  We buy the (inexpensive) pro version but the free version works fine.  Love how I can "print" from multiple areas and as long as I have the "merge" tab on (and it's always on), it will automatically put the new doc at the end of the ongoing pdf.  And then to rearrange and/or delete pages, is a snap.

In order to just bring up (and maybe re-save?) something, try Sumatra.  It doesn't have the power of Cute or Foxit but it's totally free and works like a charm when there are issues.  It can open pdf's that my other programs -- including Adobe and Cute -- can't successfully open.