If you can, buy your monitor from someplace that will let you see the
same monitor (exact same, not the same monitor) that will be on your
system.
Quality varies greatly from monitor to monitor. Personally, I've
seen Sony Trintrons that have lower quality (in terms of convergance,
brightness, useable image size, etc) than my $300 - purchased locally
from a hole in the wall - 14" Samsung.
IMHO, convergance on a color monitor is largely a function of how
much it bounced arround when it got shipped.
2. Supported hardware :
Everyone supports Adaptec 154x boards.
Everyone supports Tseng ET4000 boards.
Everyone supports Western Digital 8003 ethernet boards.
Don't deviate from these unless you are SURE your Unix vendor will
support your hardware.
3. Software
This is the hardware FAQ, but you're quoting prices for X, etc :
BSDI has a real nice implementation of BSD, bundled with
TCP/IP, NFS, an Xserver, all of the clients, GNU tools, full kernel
sources, etc, for $1000 including full source and binaries for everything.
Linux - we have X11R5 and most of the GNU utilities available in
binary form, for free. TCP/IP is in alpha test, so are SCSI and QIC-02
tape drivers, and we have beta support for ISSO-9660 / Rock Ridge on CD ROMS.
There's also the Jolitz port of BSD.
--
Microsoft is responsible for propogating the evils it calls DOS and Windows,
IBM for AIX (appropriately called Aches by those having to administer it), but neither is as bad as AT&T. Boycott AT&T, and let them know how you feel.