with due respect to plool, i don't think he understood the question.
typing "256MB Radeon ATI HD 2600 XT" into google took me to
http://www.sapphiretech.com/fn/produ...=179&grp=3
it says it has:
[ QUOTE ]
two integrated
dual-link DVI display outputs
* Each supports 18-, 24-, and 30-bit digital displays at all resolutions up to 1920x1200 (single-link DVI) or
2560x1600 (dual-link DVI)
[/ QUOTE ]
this means that it supports dual-link dvi.
repeat this for the other model names you are considering, and you'll be fine.
also, if you're just using your pc for interweb, poker and email, then that hard disk will be sufficient. you can always buy another one later, and they're relatively easy to install. depending on the retailer, you simply have to consider the benefit of a larger hard disk - if you use it for much video, you'll almost certainly want a bigger one.