(Note that this comment DOES imply that you won't get many research ideas just by being exposed to work-related issues. This is my opinion, rather than a fact. Based on my experience, it applies to accounting, but whether it extends to other business fields, I don't know. I'd guess it does.)
i disagree with that.... in my case, my work experience completely changed my research interests and helped me form and shape my direction which i eventually will be pursuing in my phd. however, i admit that during this work I have always "kept in touch" with the academic world by reading related academic papers that related to problems i found at work.
having said that - I agree that in terms of admission (and admission only), and if the choices are working X months in HR vs. working same X months as RA (or similar research position) - you'd be better off doing some research stuff (I had both on my resume... and X was rather large).
and just to add another confusing aspect to my already confusing post - i believe that it is not the experience itself, but what you make of it, that are important - and this should be shown on your SOP. so if you eventually worked as HR and it helped you in shaping your "PhD soul" in a valuable way, then tell this story in the SOP, and it will be better than just saying you've been RA for 2 years.