In addition to what Anthony (acg) said, Xeon's are not better that I can see. They are slower on the (max) frequency and btw both the i7 and the Xeon don't have on board graphics. OK, it depends a bit on the type (of i7) but now this is also related to something you may have overlooked : the CPU socket.
So if you go for the LGA2011 ... in there both go i7 and Xeon. This can be very convenient. Btw, where our PC could only focus on the X79 chipset for this, today this is X99 and don't ask me how the choices are for that at this moment (I just didn't investigate it - I think Michael did).
In the end this is all about the existence of MoBo's and for LGA2011/X79 there's one reliable MiniATX only (that I know) : ASRock. Small downside : The X79 version was taken out of production a year ago, and I assume it will be replaced by a X99 version. Or not at all ... and then it stops for small MoBos.
The only positive that I can think of with the Xeons is the number of cores. Like 20 (hyperthreaded) if you want (or even 24 - I forgot).
Thinking Xeon is a bit dangerous at this moment, because new I7's will be there with more cores than the 12 from today. Or are already there - again I didn't look. But the 12 cores (or native 6) will be 16 ( 8 ) at least because the i7 actually already was that. But it couldn't be utilized because of not enough pins on the chip possible. I do this by heart : I suppose that LGA2011-3 has the sufficient amount of pins so the already existing 16 core i7 (design) can go in against a fair price.
Now I should start digging myself I suppose ...