BUT aside from cost considerations (PCs being MUCH cheaper) my experience over the years is that macs are a much more stable and reliable platform.
I can understand this approach, if you omit the fact that PC platforms are open to many MFR's, which are usually what goes wrong with PCs when you add or upgrade differnt components... compatibility.
if you are upgrading a MAC or adding something, you have a couple options and that is it, also helped "regulate" this is the OS, being limited to a degree(this was the case unless you ran Win for Mac or now Parallels). These things do make a MAC more stable in a apples to orange analogy. In a sense that is good for the masses. I cant get around the short comings of how my drives and software is structured on the MAC/gui, and that is the heart of the system for me to see where things are. I use ACDSee3pro as a image organizer/"dam" and goto app for starting and ending a project. (they improved a great deal with this 3 Pro release). Otherwise as long as I get the work done fast, I could care less what is running it. Do I like the way the MAC looks, YES!, and thats why I have a G5 that gets used once in a blue moon for layout app, sometimes capture. there are 8 systems,7 PC's. Now 3 with Win7.
If you know your way around the Windows Explorer, and are comfortable with it, and you can unistall and update a driver or 2, I can't see someone getting the MAC ...perhaps unless you have clients to please, or like to get the "artist" affirmation, because some AD doesnt know anything other then a MAC for design(sad and pitiful really). I have put together 90% of my systems with my chosen components. But many people dont care, and dont want to know...more power to you....get something prebuilt with a warranty...done.
For a studio world, a one system approach gets stretched right out the front desk. You need accounting, crm, you need FTp's to regularly manage , you need Data storage Sas, or SATA port multipliers, you need backup solutions automated for your TB's of off system data, you need an email machine that is backed up with client lists, #'s, a Print server, an editing station, a concept design station perhaps for prepress, a capture system, calibration, spectro profiler, dual 30" screens, a prepress screen, a 30" screen for captures for 100% size detail focus crop... and things add up. YOU WILL NEED TO UPGRADE or buy a new system at somepoint....You might have 3 or 5 +people working, or maybe it is a solo gig, but know that 1 machine cannot do it all correctly....(any platform will start bloating when you have x-GB of emails etc). and because you dont put all the eggs in one basket as Any and all systems can fail in a HDD(as over the years, that is all thats really ever fialed for me.
If you are not familiar with a PC and the way it "thinks", get a MAC, and be happy. In all honesty, not wanting to know, is bliss! really! If you know your way around a PC, yuou should have known that a CLEAN install is going to make all things work better as you installed a # of apps you never use, and with fresh install things will run faster/smoother....regardless if WIn7 could or could not upgrade. Win7 shipped with a sheet of paper warning for users that they will need to install a fresh clean copy. no upgrade from XP. Even shipped with a compatibilty tool. Then you have 32bit users switching to 64bit...fresh install. ......oooh, enough pc/mac talk :-)