To provide a counter-argument, my wife has a BS in ME _and_ a MS in ME, which she got in rapid succession. Her work in graduate school is _extremely_ relevant to her current job, which she got shortly after finishing up school. Your generalization that intern/co-op experience isn't good enough is almost hilarious - you don't think employers care that you worked a few summers for a major aerospace or electronics firm? I rather think that they do, because those references can be _very_ helpful in determining the quality of an applicant.
Now, let me provide another bit of advice from personal experience: going back to a good school full-time once you've started working is extremely difficult at best for most people. I'm not saying it's not doable, but if you've got a spouse and possibly kids you need to help support, the option is difficult to exercise. _If you want a graduate degree, best to do it up front._ You may not have the chance later.
Personally, I didn't care to go for an MS in CS (or an MA in Economics), but I did wind up going part-time for an MBA. It is not a ton of fun to back to school at this stage of my life, useful and interesting as it may be.