Congratulations on your choice! I don't know the XPS series that well but I know that Dell make very, very nice machines. I want to buy a new machine somewhere next year and Dell is definitely included in the options to consider. But, obviously, I'm also considering other options, like the new HP Blackbird, maybe an Alienware Area 51 but I'm also playing with the idea of building a machine again ... which also sounds very appealing to me.
My experience with Dell is very good; I never had an issue with my machine on that level. The issues that I had were all software related and I have myself to blame for that

See my signature for my specs; but keep in mind that this baby is nearly four years old! I bought this machine in January 2004 and I am still very satisfied with it. It came with 1 GB of RAMand an ATI Radeon 9800 Pro which was considered a high-end ($500) card back then.