[Anteneprorid]

Yes, have a plan. Most of the Marines I served with that reenlisted did so because they did not have a plan when their enlistment was up! You don't want to have 8 years in and then get out because you really didn't want to re-up the first time! At that point it is a waste to just let 8 years go!
My plan was to go to college. I actually worked part-time at the Home Depot before and after getting out of the Corps to make sure my finances were in order. I also had the G.I. Bill but it was far less then what you will receive. Don't let others scare you into staying in by saying that the economy is really bad or that the job market is horrible. They said the same things when I was getting out. Even though it is a tough economy now, don't let that fact alone sway your decision. Use the skills that you learned in the Corps to make it on the outside. If you are going to college (which isn't a bad plan) and you use up all of the G.I. Bill before finishing school, do not pay for the rest out of your pocket. There are plenty of employers that pay 100% tuition (some up front), so no need to foot the rest. I would suggest that you attend an actual campus college and avoid the on-line schools especially if you want the college experience. And you might want to give serious consideration to maintaining your affiliation with the Corps by serving in the SMCR because trust me, your civilian job will lack in the good qualities that made serving memorable.

-Good Luck