Well, PC3200 ram is faster unless you're OCing that crucial pc2700 ram. I myself just use generic samsung pc3200 2x512MB ram. I'd probably cost less than your crucial ram setup and you get 256mb of extra ram to go with it. Size of ram in this case is more important than speed. Cause if you're using a lot of your HD swap space, you're gonna get some pretty bad preformance bottlenecks right there, and most games reccomend 1gb of ram anywho.
Btw, ram isin't the most important part of a gaming comp.. I'd say it's the 4th most important. Videocard, cpu, mobo, then ram.. well, maybe psu is more important especially nowadays with higher requirements of wattage.
Yes, just get the 2800+ cpu. preformance diff is like you said, not huge. If you ever felt the urge you could always OC it to a 3000+.
Now, that vidcard's good, but there's better. If you can try to get a 9800 pro. Damn good card, even the sapphire 9800 pros (make sure you get one that's not a black PCB! they come with cheap ram that fails!). Visiontek's some random other brand, which I havn't used. I think they'd be more reliable than sapphire, cause yeah, sapphire had a bit of a dodgy past there... Hmm, I dunno how much better a 9550 would preform over the 9600 pros.. find a benchmark, might be better to just get a 9600 pro man. www.tomshardwareguide.com
check there, cause my school day's over and I gtg home inna min or so.
Btw, trust in samsung, they make high quality monitors n' ram, so I'm sure that HD and optical drive is plenty great.
Now, soundblaster audigy there... hmm, soundblaster sucks for drivers man, my soundblaster audigy gamer has crap new drivers that actually make them worse, sound won't stop popping. I'm not sure if creative has made up for it with the new audigy 2 series man.. so it might be hit or miss. Try using the onboard sound on that mobo (which will save you good cash you could spend towards a better videocard like a 9800 pro), if it doesn't cut it for ya then buy the audigy 2.