Do you go full 5.1 with your sound card? Or just 2 channel stereo? PCI is dead my friend. But if you really want it, you can go with another mobo. I recommend either ASUS or Gigabyte. EVGA has some decent ones too. Here is some more info for you.
Motherboard: You want to stick with either a Z68 or Z77. These will allow you to OC your CPU. If you get an H77, you'll be stuck with a locked CPU, even if your chip can be overclocked. Z77 motherboards are compatible with both Sandy Bridge and Ivy Bridge processors. So if that 2500K isn't cutting it a few years down the line, you can upgrade to an Ivy Bridge i5 or i7. The 2500K that I recommended is a Sandy Bridge proc.
CPU: Stick with the CPUs that have the "K" designator. This mean they are fully unlocked and can be overclocked. All other Intel chips are locked and won't go any higher than their rated Turbo Boost speeds.
GPU: Blender is awesome because you don't need a high end video card to do some decent work. Nvidia tends to be the one that works best with Blender as well, so a 550Ti should be good enough. If you ever decide to run something like Maya or 3DS Max, then it's time to look into a workstation graphics card.
RAM: Blender and Photoshop love RAM, and 8GB should be plenty. But if it starts to get sluggish on you, just add another 8GBs.
OS: Windows 7 64-bit is your best bet. It might not matter to you, but Home Premium is locked to 16GBs of RAM. If you ever want to go above that for whatever reason, you're going to need W7 Professional.
Let me know if you have any questions.