Hopefully, you already have an idea of what constitutes a "good" price for your route/market. I've seen some very good prices for Feb 2011 out of our area already ... mostly on the discount carriers.
If you are flexible about when you can fly (e.g. vary your dates by a day or two each way, etc), you might get away with waiting; however, if you need to fly on certain/set dates and see something reasonable now, I'd purchase the tickets.
I find that if you are going during your areas school "spring break", the Friday/Sat departures and the Sat/Sun returns fill up fast. If you are not tied to your areas college and/or school breaks then you might be okay with waiting.
It's usually just a crap shoot ... but if you see something good out there that meets your needs, I'd be inclined to purchase now.