ok, so, you'd better give a "budget limit" to this thing or you'd be swamped with options, not all viable.
first really important thing: do you already have a monitor or will you buy a new one? Ideas on resolution? This will make the graphic card(s) requirement change dramatically.
I'd say: get a quad core, prices are going down from january 18th coz of the new i7 cpus:
If you want to play games, 1 powerful card would be enough with almost everything up to full hd res, but as I said if you get a 1680x1050 monitor you won't even need the most powerful one or a sli-crossfire configuration. Also, as it seems like you wanna watch movies too with this machine, you gotta consider 2 graphic cards = double the heat, 2 fans moving = more noise = more heat to be dissipated.
my take is:
a good, spacious case = Cooler Master cm590
a great cpu= q9550
4 gb of good 800mhz ram with good timings (no need for higer frequencies if you're not into overclocking, which is something you won't need to do with such a cpu, basically, at least not for a good while)
a x38 based motherboard (Asus p5e, gigabyte x38 ) not the latest chipset available but really powerful (especially if you plan to use 2x graphic cards, as it has 2x 16x pci-e slots ) , will be cheaper and powerful.
a good SILENT power supply (Corsair hx650 or Enermax modu/pro 82+ 625W)
A good video card, balanced with your screen's resolution
for the hd, a better solution would be buyin a mono-platter, fast (and relatively silent) one as main hd for OS and programs ( WD aaks 250gb is ohkay) or better yet an SSD drive if you REALLY wanan spend a lot, then add another bigger drive to store data.
I'd say add a blu ray RW and you're set.
for the "recording" tips, give us some more infos on the "professionality level" you want to achieve or tell us something more about the things you want to record/edit, prices and models vary too much to give a suggestion based on just the "I want a really good sound card" bit.
One thing, if you want a SILENT pc you'd better buy some aftermarket heatsinks both for cpu and gpu(s).
For the cpu I'd suggest a Zerotherm Zen fz120, cheaper than others and VERY effective.
For the gpu the best bang for the bucks is the Arctic Cooling Accelero s1 rev.2 , especially if you go for ati cards from the HD48xx series (great performance and good prices, and you can buy one, check if performances are godo for you, if not it's easy to add a twin and go for the crossfire setup).
Add schyte slipstream 12cm fans in intake/exhaust for the case and to both the cpu and gpu heatsinks and you'll have a reeeeally powerful and relatively low dbs-producing machine. That is, assuming you'll keep the fans' rpm 800> , which is achievable either buying a rehobus (such as the wonderful scythe Kaze Master) or simply buying the 800rpm version of the fans.
here you go.
/silent pc geek mode off.