I was a college prof for 6 years and I agree with others who've suggested, "if you can afford to go to school and not work (even for a semester or year), then do it!!!"
Not having a job will allow you to fully immerse yourself in your studies and in the gestalt of the university experience (which extends way beyond book learning). You'll be free to attend on-campus events, lectures, study groups, etc.
After a lecture, you'll have time to head to the library if you're motivated to read on, or have coffee with classmates and faculty to develop the relationships that really sustain you during college (and for years thereafter as you all enter the workforce).
If you "must work" while in school (and I worked full time through both my masters and PhD), it's certainly possible to do so and there are even unique rewards to doing it. The theory you learn in school is often directly applicable to problems you're facing at work and that can be helpful on the job. But if you have the luxury to take some time off, immersion can be wonderful, particularly if its been a while since you've been in school.
Just my $.02