I've been looking at replacing my home desktop system with something a little newer. Gone are the days of AGP, DDR400 and HyperThreading. These days it's all about the number of cores and PCI Express. The Mac Pros are a very tempting machine - being Intel based, you can still run Windows XP on there if required for all those important programs (such as Half Life and CounterStrike :)).
This is until you look under the hood a little. The majority of the hardware is fairly generic - until you get to the memory subsystem. Apple have chosen to go with FB-DIMM memory while the rest of the generic industry has gone with straight DDR RAM. This means that on average, the memory latency involved with the Mac Pro system can slow them down on CPU intensive things (like Half Life etc) by a whopping 10%. Add this to the expensive base price of the Mac Pro compared to generic hardware and things get a little dissapointing.
I am certainly hoping that Apple look at addressing this (no pun intended :)) and looks at removing the FB-DIMM based RAM on the Mac Pro and instantly giving their lineup a 10%+ speed gain - bringing it inline with the rest of the industry. Something I doubt will happen however :(