Main suggestion would be to contact the relevant groups, UK - RNIB click here , assuming your in the States as you used $`s, US- NFB homepage click here and products page click here .
Again for the UK AtoZ of specialist computer companies click here .
Top of the range graphics card isnt needed so you can save some money there, a reasonable sound card is needed for JAWS, if no sound card (potty not to have one) a refreshable Braille reader or hardware speech synthesizer would be needed.
If the user has any sight at all, a Large Monitor, Many Keyboards out there for the Blind including large keys, bright coloured keys etc, might not be required if they can touch type.
Fast CPU and a decent amount of memory (are probably the most important things to look at, most new machines are more than capable of running JAWS.
But as above the best thing is to get intouch with the Blind associations and/or talk to Blind people who are using computers to find out the pitfalls etc, some purpose built products are very expensive and may not suit all individuals.
Hope thats some help.