What graphics card is most appropriate for high-end 2D print design?

1. The card should be able to handle Adobe Creative Suite 2 and
QuarkXPress applications.

2. How much memory is ideal? 128MB, 256MB or 512MB? ? How much is justified?

3. Which type of processor should be used? Radeon, Quadro, Geforce,
Parhelia? (I understand that these are from different companies - I am
not asking which company but, for example, Nvidia makes both the
GeForce and the Quadro. Within the different companies are some cards
better suited to graphic design?)

4. Which interface is ideal? AGP vs PCI Express.

I am searching for ideal but justified components on the card. This
means that I want maximum performance for the tasks specified ? not
just a high-end 3D card ? without overkill.

I?m not a gamer.

I have a very high-end workstation:

Dual Xeon 64-bit 3.6GHz (2MB L2 Cache)
2GB DDR2 PC3200 400MHz RAM
250GB SATA -> Boot Drive
2 x 300GB SCSI RADI 0 -> Data Storage
The motherboard has a PCI Express slot.

Budget is of course a factor. I'd like to keep the cost below $1,000 -
well below if possible :-)

If your requirements for your graphics card is only for 2D graphics
purposes, I would recommend you to look more into things like DualView
and DVI connectors, maximum resolution, refresh frequency. AGP,
advanced graphics port was designed to raise transfer rate between a
motherboard and a graphics card. The reason for this was to
decentralize 3D graphics calculation process to graphics card so that
CPU could have more processing time to deal with other things like
physics calculations. PCI Express is designed for dual graphics card
solutions where the lower part of the screen is being calculated by
one graphics card while another card calculates upper part.

I would recommend you to invest more to a well balanced computer where
all of the components are adequate. Matrox can offer graphics cards
for the needs of professionals.
http://www.overclockers.co.uk/acatalog/Matrox_Graphics_Cards.html

I am also a graphic designer (Adobe Photoshop/Illustrator)

My suggest is use NVIDIA Quadro® FX (4500,4400,4000)

AGP or PCI-E is "no difference" in 2D graphic design.
if you current use a AGP 8X board, buy AGP version,
if you plan to buy a new mother board, choice PCI-E version.

The only problem is Quadro FX "really expansive". But there is a 
good way: Buy a GeForce 6600GT or 6800,, and download a program name
"Riva Tunner",, it can modify your 6600GT or 6800 become a
Quadro FX for free!

it's really work, and cheap (about US$150) and high performance.
(also great for 3DSMAX/Maya)

and, if some day you like to "DOOM" or "HalfLife",, you can easy
"tune back" to GeforceFX then take your 3D performace.

platdesign, I know it sounds strange, but leedashone is right -- the
card you're looking for is a NVidia Quadra, which can be achieved by a
simple software program that adjusts the way the hardware is accessed.
The GeForce is the same card, but with a different configuration so
that some features are "locked out" and others turned on for ideal 3D
gaming. If you want a high-end but budget-rate card, this is an
excellent solution -- the Quadra is a great choice on it's on, and
this bargin price for the same quality makes it an excellent buy.