Do you "really" need all of those plug-ins? Wordpress handles around 90% - 95% of your sites SEO, so you really do not need the all-in-one seo pack? If your site is choking at 5,000 uniques a day, its time to upgrade your hosting package. Maybe its time to look into an entry level dedicated server or a high end Virtual private server. I'am running 3 vbulletin forums, 1 mybb forum, and 2 wordpress blogs on a quad core dedicated server with 8 gigs of memory. 1 of the vbulletin forums gets an average 10,000 - 11,000 uniques daily. If your getting 5,000 daily, its probably time to upgrade.