Spending $1000 on an Intel CPU seems a bit much when I can get a AMD CPU that gets the job done for $200. The first two GPUs seem a little expensive to me at $1500 but I don't need to go as cheap as the second two $150 GPUs. I can't find a couple of those cards on Newegg.
Perhaps I should provide a little more information. The computer will be used for designing machinery, I won't be playing any games on it but I want to be able to work smoothly with good graphical settings in Inventor. I'll be using an ASUS VW246H 24" monitor and possibly a second, smaller monitor to simultaneously display AutoCAD drawings. I'll be running Windows x64, either XP or 7, I don't know which would be better - I've been using XP for a long time but I don't have an x64 install CD and I think those are hard to come by. I'll probably use 8GB DDR3 RAM.
Since you suggested the AMD 1090T in your second combination, does that mean it would be more suitable than the 1100T? You didn't directly answer that question.