To answer the original question, the entire official SF series has hit everything BUT WWII. The only other part missing is, of course, the most modern avionics of the last couple of decades. Of course, modders have filled in MANY blanks for the SF series, which was the entire point of SF anyway... For me personally, the earlier sims tug at my youthful memories, recalling the aircraft I read about in my mis-spent youth... (can I get a refund, USAFMTL?) The most modern jets have no nostalgic pull at my hearts memories...
As for graphic loads, my current machine is nearly maxed out with upgrades. I can go one step better to a 7600 x 512mbDDR video card, and that will be it. CPU is maxed, RAM is maxed... I would dearly love to be able to break down and buy a new monster Alienware something or other... just not right now. As for Windows Vista, the thought of an OS that requires 15GB of space is just too bloated for my mind...
ML