With $2,200 to work with youre doing pretty good, we can definately work with that.
I remember in your first post you were interested in going SLI. Definately a great way to show off your uber gamerness. But in all honesty it's only good if you plan on running benchmarks and pwning them. Jim and I both did some in-game tests with our SLI rigs and noticed that SLI in some cases actually dropped our FPS, still don't know why. I would lean towards Kemp's choice of an x1900xtx. Those cards are just wicked powerful, period.
I totally second the Conroe movement. I don't think there is any better way to go right now. Sell whatever processor it is that your friend gave you, it's more than likely low-end if he just
gave it to you. Now if it's FX-xx then by all means hold on to it and we can work around that

Anyhow, Conroe is just now hitting retail shelves so you're trying to build a computer at the perfect time mate. I'd recommend the new Asus P5 ??? (can't remember the last numbers) which is the same board that Jim just picked up. Supposed to be a pretty darn nice little board with some decent clocking options built-in. You're best bet for the processor is going to be the 6600, as it's the most cost effective. It can easily be overclocked to 6800+ speeds.
For the RAM... I don't really know a whole helluva lot about the new lineup of DDR2 so I'm not the one to comment on that subject. It's the one area that I don't follow up on as much as the others unless I actually have a need to (ie. I have a rig that uses DDR2).
PCP&C is the only clear choice for a PSU if you have the kind of money you say you do to build a rig. Easily the most powerful, stable, and reliable PSU's on the market. I think everyone on this forum would probably agree that you can't go wrong with a PCP&C. The 510w Turbo-Cool would probably be the perfect choice for ya.
Cases, wow there are so many awesome cases out there. I think one of the cases that interests me the most right now is the new Cooler Master Stacker 830. I personally thing the new design is absolutely wicked. The case itself will get you a lot of room to spread stuff out and give you more expansion options in the future. Also a great case if you ever decide you want to watercool, you have plenty of room inside for all of the parts. Other than that Lian Li cases get my vote. I rocked my PC-75B for a long time, and was definately one of the easiest cases to work with I have ever owned. Roomy, sexy, and functional; that's all ya need and exactly what Lian Li delivers! I quite like that new little cube'ish case that (Raven??) posted about, i'd be looking in to getting one of those mefinks.
As far as CPU cooling goes, there's a million options out there for ya. I think Core 2 Duo uses a different heatsink retention bracket than P4 but I'm sure there's already an aftermarket bracket to allow you to use P4 heatsinks if this is the case.
Hope some of this info helped ya out a lil' bit.