Personally, I'd prefer an AMD processor (every bit as good, but cheaper), bags of RAM, and would probably "build my own"
AMD 'clocks' FX processor at 8.429-GHz
September 14, 2011
Advanced Micro Devices Inc. has announced it has achieved the Guinness World Record for the "Highest frequency of a computer processor," by running an 8-core FX processor at 8.429-GHz.
A bit of overkill for your requirements Poly', but obviously AMD still have something up their sleeve.
It seems a shame that you couldn't live with Linux, but the likes of Fermilab and Cern are happy, along with other scientific organisations to put together Scientific Linux 6.1 based on RHEL.
Seems a shame that your dongle didn't work. I have often found that in situations like that, six months is a good time to look again at a more current distribution release as it takes time. it's not the fault of Linux that the dongle doesn't work, given that it was designed with Windows in mind with collaboration between the various organisations, but Linux developers get to see the gear only when it hits the market. Wifi used to be a problem, but Linux has caught up. Broadcom eventually OpenSourced it's drivers because they realised that they could sell more hardware because Linux users were on the rise, albeit a very small one.
I wouldn't mind betting that of the 40 websites you have a presence on, that more than 50% have a significant Linux/GNU Open Source content or OS.
You could do worse than have a look at what Aria,co,uk are flogging. Prices are quite keen. buy a simple business machine of the appropriate spec and then load it up with as much disk as you like and your own OS of choice I notice that the price of SSD's is coming down nicely. One of those would make an awful lot of difference to the performance of your system Windows 7 should be good and Linux should go like the proverbial off the shovel. Virtualisation is also good to go these days and allow you to run a guest OS. Apparently Windows 7 runs faster virtualised on a Linux box than it does natively. Now explain that if you can . . .
Plextor M2S Series 64GB 2.5" SATA-III 6GB/s Solid State Hard Drive is now on super special at £59.99 including VAT.
Virtualisation might be of interest to you, but SSds should be a definite must have for system speed, with most of your regular user files on regular rotating memory devices.
In a year or two, when you are hankering after more SSD, then the sizes will have gone up and the prices down.
AMD may not always have the fastest processors, but bangs for bucks it is a very good bet.