Desktops are easily configured for ones needs. For photography, you can not beat a massive amount of RAM. My graphics machine was upgraded last summer, to 24GB RAM which cost just slightly more than $200Cdn. Interestingly, I have actually maxed it out a couple of times! It is an enormously powerful machine, since it is primarily used for 3D modeling and rendering, but allows me to work in Photoshop while it renders in the background. If I was using it only for Photoshop, I would not have needed anywhere near the CPU power.
A friend configures my machines which lets me define their purpose. The machine that was replaced by the above was rebuilt to be a secure storage machine with a large fault-tolerant Level 5 RAID. It has a somewhat old, but still lively quad-core CPU, so I can use it as a render-server, allowing me to render on the network. It will also be used along with my stack of synthesizers as a music production machine.
I am writing on a high-resolution 30" monitor with a machine fine-tuned to A/V acquisition, editing and consumption. Old, and modestly configured, has a video and an audio capture card, does my scanning, and the monitor also is my HDTV. The output of the synthesizers is recorded and edited on this machine and it serves for any multimedia project I take on.
The point is that you can define the tasks you want optimized, and for the most reasonable price, get the machine built to serve your needs with minimal compromise. Buying off-the-shelf, gaming machines work quite well for photography, but you are paying for a lot of stuff that just is not needed. Having a photography machine built, means no money is wasted, and the machine is a great pleasure with which to work.
