Q Xeon and QE, which is better for me?

Well, if you want a workstation class system then go with the Xeon based system. You will be paying more for that privilege. If you want to wait the Skulltrail Extreme Desktop board might be what you are looking for. 4 PEG slots, Dual processors for up to 8 cores. 4 DIMM channels using FBDIMM's. That is a lot of bandwidth. You will even be able to get DDR2-800 FBDIMM's for faster access.

Be aware that if you go this route you will need to spend money on excellent cooling for the beast.

Or go with a new X38 designed board. That will allow you to get into a less expensive system but do the same type of overclocks you could do with the Skulltrail. Will cost much less. It comes down to needing 4 or 8 cores for the type of work that you do.

Or go with a AMD dual processor system that will allow you to upgrade to the latest Opteron. It has been proven that the Opteron's have better floatingpoint and I believe that is what Ray Tracing nees in abundance. Not to say that the above mentioned Intel stuff will not slow you down too much.  

But what is meant by this please? How do I know if I need a workstation class system?

You pay for the more advanced chipset including the higher cost Graphics subsystem. The workstation graphics are usually standard graphics cards with more memory and drivers design for OpenGL. If you don't need that or you don't want to spend the additional money or don't need 2 processors with a total 8 cores then stick with a High End motherboard and go with a quad core from either Intel or AMD.

Well I work at Intel as well, and I can say from personal experience that Xeons are NOT a Desktop CPU. The best CPU I could recommend to you for multitasking; and I'm sure other will agree with me when i say this, is the Q6600 CPU from Intel.

Also, if you are debating if you need a workstation based system you can tell by how much work you're actually doing on your system at the same time. Like using very intense programs such as video encoding while simultaneously compiling programs or whatever, case in point is, you're stressing your CPU a lot!

If that is the case than I still advise against a Xeon CPU. I highly recommend a quad-core desktop based CPU, albeit AMD or Intel. Reason being is that if you were considering a Xeon in the first place than obviously you're using a lot of CPU usage. Quad cores help solve that issue.

Here's the Desktop and Server based CPUs I would suggest to you, and no matter what, you'll get a great product, but try to pick something that will be as much of a benefit to you and the way you use it as you see fit.

AMD Opteron 2347 Barcelona 1.9GHz
http://www.newegg.com/Product/Product.aspx?Item=N82E168...

Intel Xeon X3210 Kentsfield 2.13GHz
http://www.newegg.com/Product/Product.aspx?Item=N82E168...

Intel Core 2 Quad Q6600 Kentsfield 2.4GHz
http://www.newegg.com/Product/Product.aspx?Item=N82E168...

Intel Core 2 Extreme QX6700 Kentsfield 2.66GHz
http://www.newegg.com/Product/Product.aspx?Item=N82E168...

Intel Xeon X3220 Kentsfield 2.4GHz
http://www.newegg.com/Product/Product.aspx?Item=N82E168...