I run a few community type sites, one similar in size as this one. Forum Pruning helps, turning off the search function is another. As for getting rid of forum sigs and stuff...it takes away from the fun.
This is a great site with a good size user base. You should be able to make it profitable somehow. I created a calgary community site because I didn't know this one already existed; else I wouldn't have wasted my time.
www.flames-hockey.com . Turns out there are quite a few now that the calgaryflames.com shut down their forum. I have a high powered server with my company that is highly highly unused. If you continue to have cost problem pm me and I'll see what I can do.
Sell add space, more google adds, etc. I've even seen some sites where they kinda slip adds automatically into the forum. its a little ugly on the eyes but it might be enought to pay for the cost of running the site.
php-5.0.4-10.5
mysql-4.1.16-1.FC4.1
and apache 2.0.54-10.3
Raid Drives
Intel Xeon™ Processor at 2.8GHz/2MB Cache, 800MHz FSB
8GB DDR2 400MHz (4X2GB), Dual Ranked DIMMs