It's interesting reading peoples views of FSX (I currently run FS9). It does appear that, Microsoft have released FSX a bit too early for all us flight simmers, as it appears that there are not many pc's around that can actually handle FSX with all the settings set high. No doubt, as time goes by, we will have pc's that can handle FSX set to high settings.
My system was fine with FS9 to start with, but as soon as I started to add all of those add-ons, then my pc started to struggle at times (this is why I have not bought FSX yet), and this is my concern with FSX - how powerful will your pc have to be to handle FSX and the many future add-ons? Only time will tell.