Hi Vb pros. My sites have grown. My server is sometimes slow.

This is my current setup I am running:
Running Linux Dedicated Server in a DC in NJ/NY
- Paying $129/mo
- Debian/fedora release
- Plesk 7.5 reloaded panel
- 3ghz P4
- 2 gigs of ram
- 120gig drive
- allowed 1500 gigs of traffic(use around 50gb)
- About 15 websites online, 14 of them are static with low traffic, one is a superstar with 20-30,000 uniques daily and 10 million+ page views monthly.
- 5 Databases
- Completely optimized Mysql with eaccelerator/data caching/php caching, etc.(when we did this, the site FLEW much faster)
- 3 vBulletin boards (superstar site with 500,000 posts)
- Receiving 100-200 new registrations daily on superstar

My superstar site sometimes is seeing slowdown with server load issues sometimes reaching 40+ when the superstar site has 100+ registered users online and 350+ guests. Then the loads come back to 2-5 within 10 mins. This leads me to beleive that

Things I absolutely need:
- Plesk 7 or higher(nothing else)
- Good support
- root/ssh access
- 120 gb drive
- 750+ gbs of allowable traffic

My budget could be around $200/mo or so.

So, with all that said, I am possibly hunting for a new server.

Any assistance would be greatly appreciated! :)