I'll just say this:
My old system (3.5 years old):
Athlon 64 3400+
nVidia 6800 GT 256MB
2GB DDR400 RAM
2x 250GB HDs in RAID 0
Audigy 4 Sound
Windows XP
With this, I would get ~12 FPS in FSX on average, ranging from 40-50 over the ocean to 2 in a city on medium to medium high settings.
My new system (2 weeks old):
Q6600 Quad Core
Factory Superclocked nVidia 8800GTX (768 MB)
4GB DDR800 RAM
2x 320GB HDs in RAID 0
X-Fi Xtreme Gamer Sound
Windows Vista 64-bit
With this, I get ~45 FPS on average, dropping to ~20 in big cities with all settings on very high except for light bloom, and autogen turned down to normal and very dense in DX9. I'm waiting for new drivers from nVidia that are supposed to help with DX10, so hopefully I can switch over and get a little performance boost. I'm also planning on overclocking my processor next weekend up to 3.6Ghz per core (FSB 1600) once I get my new CPU cooler, which would apparently really help with performance as well.
This is how my sim looks now:




I'm extremely happy with the quality I'm getting and the performance I'm getting and I wouldn't be happy if I bought a whole new computer, and all I got was "slightly" better than FS9. I think every game should be developed to bring the best computers out there to their knees, but not developed only for those computers. I think the ACES team did an excellent job with FSX, because I could do anything I wanted in FSX with my old computer and still get decent performance with the graphics turned down. But, I would not be happy at all if ACES developed FSX with my old computer in mind and "dumbed it down" for older systems, so that when I got my new one, I wouldn't be able to experience all the new flight models and visuals and everything in FSX like I am now.