Sorry have to agree with the HR are a waste of time brigade.
HR are very useful for the myriad of internal company matters which result from employment law, WTD, benefits, pensions, et al.
I think that they should do exactly those things i.e. personnel but have nothing to do with the recruitment process as in most industries that I have experienced they are absolutely the last people to have any clue as to what is really required to do the job.
Most decent companies appear to have people who do the job and manger of those people doing the interviews thank god with HR doing nothing more than provide a filter for requirements and providing information at interview.
Wish this was the aircrew norm myself...