Do I need the Multi-DB plugin with my site?

Sorry about selecting the WPMU DEV Dashboard, I asked for support from the Multi-DB plugin and that required choice was not listed.

I am interested in the multi-db and I wanted to check to see if you think I need it?

I am creating about 60 to 80 MU sites that cover a different category in each site like plumbing, roofing, etc... I am creating 270 pages for each keyword or search term and the 10 additional pages normally with each site. Some sites I have 20 keyword phrases I am creating pages for. Those sites will have 270 X 20pages = 5400pages I don't expect more than 80 websites with 27,000 pages, although I may add more later... who knows... I read your Usage tab instructions which said 1-5,000 blogs/sites you should be fine with your WordPress default database. Since I am not expecting more than 100, and these are for my own advertising use and there wont be multiple users, do I need multi-db?

I expect a lot of traffic with that many pages floating around on search engines. I purchased the largest dedicated server host gator offers and had them set up a special caching mechanism and I am also using WP-Supercache. Do you have any other suggestions?

thanks,
David