In ways yous computer is good, in other ways it isnt. AMD aren't really the way to go, yes it will do the job, at a low price and cost. If its in your budget go for the Intel "i" series. An i5 750 or i7 920/930 will do the job great, an after market CPU Cooler will help you crank up the speed for better performance. Your GPU (Graphics Card) is very good, but be warned ATI don't care about us FSX users and you may experience issues with AA etc. Nvidia are good for FSX, a GTX 275 or 285 will do the job great, but if you want high performance you can go for the new cards like a GTX 480 (thought it is VERY expensive) maybe a GTX 460 or GTS 450?
Everything else seems good. I do assume this is for FSX too, if its for FS9 then it would run that fine.