8 years ago, I decided to get a job instead of continuing onto my PhD. I already had a Masters, and felt pretty ok at the time. But as has been said, it's really hard to get back into the swing of things. I'm financially set, but at a block for career advancement without a PhD (and it's pretty hard applying when you've been out of school for so long). You've got to do what's best for you, but if i could do it over again I'd continue on for my PhD instead of going the job route.
A 2nd option that I haven't seen listed could be that your current employer might consider keeping you on, and that would supplement your graduate studies income. Perhaps not full time, but perhaps part time or as a consultant, depending on your role? If nothing else, it never hurts to ask.