I want to create videos on a fairly regular basis, but don't think the frequency would be more than once every eight to 12 weeks.

Would purchasing a camcorder be a good idea, or should I do more planning and scripting, then rent equipment that is better than what I can afford to purchase?

Depending what you are doing, if you're going to be making commercials or other productions for people I would rent, but include rent costs in the budget.

If its for yourself, I'd buy it. Usually having a camcorder around can be useful.