A normal 22" is 1680x1050 = 1.76 million pixels.
A good 24" is 1900x1200 = 2.28 million pixels (cheap 24" are 1080p - 1920x1080 = 2.1 million pixels)
Yes, you will get slightly less frames on the 24" but that's where the 1gb version of the 4870 will show you why it's $100-110 more than the 512mb version.
BUT, if you want to save $250+, the 512mb 4870 with a 22" screen is still I NICE setup, especially if you're currently at 1024x768 / 1280x1024 with an 8600gt class card. But if I had the money, I would for the 1gb model and a 24" screen.
The i7 chips won't drop in price for a long time. They'll have to clear out the current inventory and ramp up production of the new parts which will take six months minimum.
I would get the Q9550 if you you don't upgrade that often. Also, Microcenter had the Q9450 (12mb cache) for $250 this last week if you're lucky enough to have one near you.
Q9450:
http://forums.slickdeals.net/showthread.php?sduid=342840&t=962981
http://microcenter.com/single_product_results.phtml?product_id=0287628
Nice, cheap P45 mobo (though you may want SLi or CrossFire with a 24" monitor for an easy upgrade as card prices fall):
http://forums.slickdeals.net/showthread.php?sduid=342840&t=934211