With the very high end Mac Pros comparable in price to PCs with the same specs, why does anyone (and by anyone I mean people in the market for a new, high end machine) bother buying a new PC anymore? Similar price, same exact specs, and you could either get the ability to run Windows or you could get the ability to run both Windows and OS X, which each have their advantages.
This past summer, I purchased a Dell Precision Workstation 690 just weeks before the Mac Pro was announced (I received it only days before). When the mac was finally out, it very coincidentally had the exact same specs as my new Dell down to the processor, the ram, even the video card. While I did get some extra perks such as 15K SAS hdds with a PERC raid card in RAID 10 as opposed to 7200 RPM 3 mbps/sec SATA that Apple offers (unless you want to get an Xserve), I keep wondering whether I would have been happier if I held out for the same machine with the ability to run OS X too.