2. The 5900's look to be the top-end cards for quite some time. Without getting too much into tech-talk, it's nigh impossible to make a GTX495 with the GTX470 parts.
Eh, a 470 doesn't pull much more juice then a 280 did, and that didn't stop NVIDIA from making a 295. It'll be made, it'll put up numbers, it will be hot, and be inefficent. Same as all X2 GPU's really.
3. An HD5770 will play all those games maxed out. Unless you plan on upgrading (your monitor) soon, a $150 card will be fine.
Heck, a 260 could max the games he listed, let alone a 5770. Right now, I recommend a 4890 simply due to its lowered price.
For performance lowest => 5770 - 4890 - 5850 => Highest, but the 4890 does not support DX11 and at that resolution you wont need the higher end cards (unless you intend to upgarde your monitor) so a 5770 should be fine
What sort of budget are you on?
Running a 5850 and an i7 CPU through a 1440 x900 screen would seem a bit of a waste to me, its a combo that is screaming out for a bigger better screen.
If you cant get a bigger screen, maybe you jus dont have room ? then a 5770 and an i5 set up may be a better alternative for you.