I still use Seagate 15K Cheetahs, Never have had one die on me! I'm sure eventually I'll change everything over to SSD, right now the technology is unproven. I use Intel Dual Xeons on Intel board, NVidia Quadro FX3700 (PNY) going to upgrade soon to the 5800 (I use CAD programs for my business). I use either Corsair, or Crucial (16GB in main box) Silverstone case, I love their cases! That covers the main components. I upgrade components as I feel necessary, not as much as I used to, too expensive. I use Samsung and NEC monitors, I would love to have the IBM T221 but I didn't have the cash (I believe $8,000.00) when it was available, but I had the luck to see one in person and WOW, what a monitor, I don't believe there's anything better being made today.
I agree with you, keep it lean and just use it for Photography and or CAD, no ITunes, no nothing. I used to dual and triple boot, but it became old. I like to mess around with Linux (for the past 10 years) and I use MAC OS X on my MBP 15" but I like windows best, (currently Vista, XP and 7). I use CS4 and Lightroom 3, I'll upgrade to CS5 soon.