It depends.  I had good luck with a resume service when I was looking into changing careers.  Every version I did myself made me look completely scatter brained.  Having somebody else look at it helped.  And it's good to have somebody else check the grammar and spelling.  But you need to make sure you tell them everything they need to know -- even if they don't ask.  If you can write reasonably well and if your resume is fairly straightforward, it's probably not worth it.  If things are a little more complicated, it can help.  For what it's worth, I used dragonresume.com.  They seem to be a fairly small operation, but they did a decent job.