Q9300 being the cheapest and lowest power penryn quad makes a great CPU to build a cheap, powerful server, or a great lowish power rig. The low use of watts is astounding.
It sucks though that it's 50€ more expensive than the Q6600 which has identical performance but eats more. The Q8200 would offer some compromise but it seems they nerfed the hardware virtualization to fend off people that would build a server on the cheap (though I wonder if the virtualization instructions are any useful)
thus there could be some space for the phenom 9150e (spotted at 154 euros)
to give you what I think of, any of those CPU could easily run a debian or ubuntu image serving desktop and applications to many, many terminals (let's say 10 or 20, made from free, junk ancient hardware and/or $90 SoC PCs) ; for desktop, net and work use, while doing some server duties. A single PC can now run an entire small company, school or computer lab.