What are the career prospects after being an RA?
Being an RA (Research Assistant) means you get to work closely with one or more post-docs and faculty members in a context that generally requires technical,  problem-solving, and communication skills -- skills that are definitely valued highly by employers.  So, assuming that you do a good job, your supervisors should be able to write strong recommendation letters for you, recommend you to recruiters from industry, or possibly put you in touch with people they know in industry.  Also, you may be able to use your RA work and experience as a discussion item in interviews.  

A lot of the industry jobs that undergrads tend to work in look (to me) like grunt-work: website development and maintenance, routine programming, stuff like that.  It seems to me that an RA would be much more preferable than those simply because it can allow you to be more creative and possibly also sharpen your communication skills.  Of course, it's possible that you have some unusual set of skills --- say, Unix guru or security honcho --- that would make you suitable for a very different kind of industry job that would be even more attractive to employers down the road --- but in my experience this tends to be rare.