Asking friends to do stuff that falls within the realm of professional activity is okay when you are in college and/or starting out.
To my mind, it is inappropriate after that, because, on one side or another it blurs boundaries - the boundary between the personal and the professional - that are better left intact.
Agreed 100%.
Things should be kept separately, and never, ever be intimate with a coworker.
Friends, family, love =! workplace.