Same here! I already had all the peripherals and a LaCie monitor, and I got the Chillblast Fusion Photo111 ...now it's this one:
http://www.chillblast.com/Chillblast-Fusion-Photo-OC-VI.htm mine has 3 drives (1 SSD and 2x1TB) and I upgraded to W7 Pro and a few other things such as fans, tower etc.
Our son checked the price of everything, and found he could not build it himself for me for much less than they could, and of course that wouldn't have had the 2 year warranty either.
By the way, I can highly recommend Chillblast for first class pre and after sales service and fully customisable PC's. Even after I'd had it past the warranty, they still help with any problems. (I had a problem with the graphics and my monitor adjustment, and their engineer managed to fix it by remote - installed some extra LaCie management software and adjusted it for me, so not even a problem with their components )
Exactly - I knew of two people in the art business: one a portrait painter who also produces books, the other a painter who also had a photographic & print studio, and both went for MS rather than Apple for photography editing and printing. The latter used Apple for the two websites she maintained, and the former did all his admin work on his Apple machines.
I'd find it difficult to use two computers, and I do have a Notebook that Chillblast built for me a year ago, and also our younger sons Dell desktop computer sat idle in a box upstairs.
The notebook will sync with my desktop, but I still need to physically move things between the two, especially if only one was online. ...then there's the Wi-Fi to think about too! Everyone in the family has iPads or phones that the router recognises as soon as they arrive, and my TV in here is a smart one that updates itself via the Wi-Fi ...all too complex these days!!!

I like a piece of equipment for a specific job, with an on and off button and no 'Tardis' type menu

....those days have gone.