As commoditization takes firm hold at the hardware layer and raw horsepower continually increases faster than demanded by core business applications, sourcing IT Hardware becomes a rewarding exercise if you are flexible in your requirements. The most successful distributors of FUD (Fear, Uncertainty, Doubt) have to be IT HW sales account teams. They will tell you anything to get you afraid to switch suppliers and many including IBM are locking their customers into longer term contracts by leveraging their remaining proprietary products to their commoditized products. Remove all the technical bias and IT Hardware is Gigabytes and MIPS. With the advent of good virtualization software even the applications compiled for proprietary operating systems don't know what hardware they are running on. Here is a rundown on specific product groups and key thoughts on sourcing.

Laptops and Desktops - truly commodities and unless you have specifc requirements for Mac OS X, go with the cheapest and the highest MTBF as the cost for these computers is in the warranty, repair and updating of software. Consider giving people that have only a need to do word processing, web and spreadsheet access, linux boxes and access to browser based office productivity tools. You can save 20%-40% if you move away from Microsoft and embrace the Web.