When buying new computers, you should save money in peripherals (easily upgraded) and put money in what isn't easy to upgrade in the next upgrade.

RAM Memory, CPU, Motherboard, PowerSupply are what constitutes the identity of the computer. You can upgrade hard drives, change the screen, add graphics cards, etc, but changing the CPU or the RAM memory after a computer has had two years, is very very difficult since it is hard to match the compatibility (a new RAM module must be compatible with both the CPU and the motherboard) and old RAM memory chips get difficult to find, and ironically, it has always been the case that the older a RAM chip is, the more expensive it gets to buy new.

New M$ operating systems always push the memory requirements to double or more.

This is the minimum RAM these OS's needed just to install (to work well it was much more, but always proportional):
Windows 3.1 -> 1Mb
Windows 95 -> 4Mb
Windows 98 -> 16Mb
Windows 2000 Pro -> 32Mb
Windows Server -> 256Mb
Windows XP -> 64Mb
Windows Vista -> 512Mb

( Take a look at http://cybernetnews.com/cybernotes-history-of-windows-system-requirements ) Bottomline:

• Choose as much memory as you can, at least 3Gb (you won't be able to add more later)
• Get a medium CPU. Never get the celeron/sempron economic lines (useless) and never choose the top of the line CPU for office computers, they costs double and you won't need more than 10% of their speed).
• Choose motherboards/cabinets with many USB ports, choose one that has USB 3.0 ports if available. Also see that it has many PCI slots. Economic motherboards have only two or three.. and it really complicates your life when you want to add a new Wifi card, a new USB 3.0 adapter card, a new soundcard (you can workaround a burnt internal sound with a new soundcard).
• Choose a motherboard that includes an onboard Nvidia or Ati GPU. Never choose intel graphics. If you need more than onboard graphics (you don't) you can always add a graphics card (maybe you don't need this except in one or two computers for the few users that really need it).
• Hard drive: choose 300Gb. For office uses, you actually only need 20Gb, but 300Gb is not expensive now, and the extra size it may come useful for when micro$oft decides to push another bigger OS. Also, it may come handy if you dualboot to linux, to ease a transition.

The rest does not matter. Chose the vendor that gives you the best warranty and the best price.

It is really really really pointless to see benchmarks or tests when buying new computers, if you want the fastest, then get the most expensive, thats it.

If you are a gamer or a computer scientist focused on algorithms, you might want to optimize the best combination of CPU, RAM, Motherboard (and GPU and HardDrive). Otherwise you just don't.

AND... never buy just looking at the brand that assembles the computer, that's stupid :-) You have to look at the components that the computer has.

"There is another organism on this planet that follows the same pattern. A virus."

Actually, a virus is not an organism.

"You move to an area, and you multiply, and multiply, until every natural resource is consumed."

Any living thing without a predator tends to be a plague.