How much does the choice of professors on my thesis committee matter? Would potential employers (for academic or non-academic R&amp;D positions) care about who is on my thesis committee?

Basically, I'm asking if there is any benefit in having more well-known professors on my committee who would provide me with little guidance, as opposed to assistant professors or research professors who are not well known but could possibly provide me with some guidance.

I'm asking because I have been discouraged by fellow graduate students from including a research professor on my thesis committee. Their reasons are that if a potential employer looks him up online and sees that he is not a tenured professor they may think that I tried to put together an 'easy' thesis committee.

The reason I would like to include this person is that he was the only member of my qualifying exam committee who read my paper carefully. He seemed to have a good understanding of my research and after I passed the exam he emailed me a list of suggestions for my future work. I think he may serve as a better committee member, although I could probably discuss my research with him even if I leave him off the thesis committee list.
For academic positions, what is relevant for your application is your letter of recommendations.  Who is on your committee does not matter (except the head).   Your job applications will not even list the members of your committee---this will only be seen by someone who looks at your thesis.

In academia, it's common that non-tenured (sometimes even non-tenure-track) faculty are on PhD committees.  This is not viewed in any negative light.  You want the most relevant people on your committee, so they can give you the best feedback, and will have a better sense of what you are doing to be able to write you recommendation letters.  Often your supervisor can suggest who to put on your committee.

I imagine that non-academic employers will care even less, as they are (typically) not interested in your research.