Videoguys are a good reference point. After reading their article I can conclude the following:
Avchd camcorders and cameras should carry a disclaimer warning customers about the need to purchase a very expensive accessory(quad or six core cpu computer) for proper hd content editing .
There seems to exist an unspoken agreement between video software producers and Nvidia( Avid recomends only Nvidia Quadro cards, another program prevents GPU acceleration on ATI card because ATI's have no CUDA, or maybe ATI settled for second best . These are just my own speculations
Workstations made by HP use great components and are capable of flawless avchd editing but cost $$$, same with Dell workstations except the company is a little sloppy with driver installation. Overall both choices are great for hd video editing.
Apple's Mac Pro is another great choice. Their computers have thunderbolt connection. It allows for super fast connectivity with accessories that unfortunately cost $$$. Hopefully price will go down on those scarcely available products. Besides thunderbolt you can purchase MacPro with top notch i7 CPU. However they don't give much room for expansion, therefore they recommend getting as much memory as one can afford(16 GB recommended)
For those of us below $3,000 budget and closer to $2000(seems to be a minimum for video editing machine) there is a choice of high end i5 unit with maybe Asus mother board, Nvidia GTX 470/570/670, minimum 8GB Ram, 1TB Hd 7200 Rpm, second system drive highly recommended.
VideoGuys also recommend sandy bridge E processor.
Working with the file full system drive really slows down the computer.
This reply is based on VideoGuys article recommended by; quotemsg
Thanks a lot to "quotemsg" for recommending the above article