bhartzer - 3:12 pm on May 13, 2011 (gmt 0)
Pjman, you have to see what it will take to compete. Look at the competitors in your industry, the ones that are currently ranking well, and analyze their sites.
Look at some of the main keywords you'll be going after. Make a list of all of the competitors ranking in the top 20 for those keywords. See how many pages they have on their sites and the approach they're taking. I bet once you do some analysis you'll be able to figure out whether you need one large site or 5 smaller sites.
Making decisions like this based on a whim is not what I recommend. You need solid evidence to base your decisions on. And competitive analysis is where I would start.