I don't think we're supposed to talk about emulators here but that's a pretty good build. The only thing is that your SSD is way too small - the Windows install alone will take up more than half the drive. You might want to consider a 500GB mechanical HD instead.
You don't need an aftermarket fan for an HTPC because the cases are so small that they won't fit, and you don't need one if you're not getting an unlocked CPU.
You'll want a real gpu if you plan to play any ps2/wii/gc games in higher than the games native resolution. 6870 works great to play most games 720p-1080p at 50-60 fps.
Otherwise that's perfectly fine for lower emulators.