you mentioned at the beginning that you wanted something that was cooler and good at games. well it seems that games are becoming more gpu dependant. so, if you invest in the SLi idea, pump up the ram, and get a 3.4 northwood, you'll have it all: cool temps, blazing graphics, and a big bugger. But for future sake, the dual core AMD idea sounds the best since AMDs are already outperforming Intels with their own clock speeds (4800+ my god!). I think Intel is doing a good job, but AMD chips do run hot compared to Prescott chips...and northwoods just seem to be superchips at this point.
If you can find them, put in a search for 3.4 northwood into an eBay search and you'll get maybe 1 or 2 or them. The final price usually ends at about 250 though (I've been tracking a few). But it is "old" technology and the s478 board is getting phased out by s775 dual cores.
-Photoshop needs lots of RAM
-Games need lots of GPU and some CPU (my CPU works harder folding than it does when I play games)
-The future of games is dual core processing (I've even heard talk of multi-cores [4 or even 8])
-Lowest heat is the Pentium Northwood series (being phased out)
-Best gaming overall is AMD
You might look into a different cooling system because the Zalman is very passive...and even though that makes it nice and quiet, it also makes it less effective...I've heard DangerDen makes a good setup, and Frozencpu.com is touting the new Apogee waterblock. But the Zalman does look good and is incredibly quiet and simple. It's all your choice, and I don't envy you with that hole your money is burning in your pocket.