Edmond, the situation is, as you know, that we are not sure what will happen to the MacPro in the future. The 2012 model is more than twice as fast as your 2008 MP. And people are getting great result with the latest quad core Mac Minis too. They outperform your MP quite a bit and cost a fraction. And they offer great connectivity unless you need PCI.
Look for benchmarks at http://browser.primatelabs.com/mac-benchmarks
If possible, wait till after WWDC in june. By then we’ll probably know what plans (if any) Apple have for the MacPro.