I have an oldish (late 90s) system, and although it still sounds great to me there are a number of upgrades I will make in the near future:
* 2x MBQuart QL1002S tower speakers (I only listen to stereo, so no surround speakers needed).
* Earthquake SuperNova MkV12 subwoofer
* Yamaha DSP A3090 7.1ch amp (yeah, don't ask... silly choice when only utilising stereo output. Let's just say I had plans, but changed my mind.)
* PC = 3GHz cpu, 2GB ram, dual 21" monitors
* Soundcard 1 = M-Audio Delta66 with Omni I/O break-out box (6in/6out - balanced + sends/returns + monitor channel)
* Soundcard 2 = Echo Audio AudioFire 4 (6in/6out - balanced)
Oh, and I should mention the headphones (Sennheiser HD555's) since I use those about as much as the main's - I guess I'm a night-owl
I'll try to find the MB Quart speaker pics to add in shortly...
Also I'm getting new near-field monitors which will hook up with the AudioFire4.