Wow 64 gigs of ram, lol, talk about overkill. I can't even imagine the game that would use over 8 gigs. Well, it doesn't hurt to have it, and you might as well since ram is sooooo cheap, even high performance ram is ridiculously cheap these days. Awesome motherboard too, good lord that thing is a beast, same with the video cards. I build all my computers too, so I can appreciate your rig.
Anyway, I do agree that separate sound cards are normally a waste as long as you are using the digital jacks. Most onboard analogue jacks are awful though, however the implementation on that board might not be that bad, at least I would hope not, given the price. The way to tell is turn the volume way up, but not playing back anything, just silence. Move your mouse around, open apps, and run programs that don't make any noise. If you hear fuzzy noises when it should be dead silent, that is because electronic noise is leaking into the analogue jacks. If you hear this, I would go ahead and buy a separate audio card like that Asus Xonar, because both your monster computer and great speakers definitely merit clean audio output. Given your rig and desires, I would go for surround sound card, not a pro-audio one. You need to make sure you get a card with clean analogue jacks though, which are mostly only the higher end HT Omegas, Asus, and Creative cards. If a card touts high signal-to-noise ratio on the audio outputs, it probably is good enough.
If you want to expand out, like I said, go for another Rokit 8 for the center speaker. Ideally you want to keep your front stage speakers identical, however the surrounds don't matter as much, so don't go blowing a lot of money on surround speakers. I would go for a ported subwoofer for some seriously deep bass. If you want loud bass without spending a fortune, newegg.com often has the
Klipsch RW-12d on sale for less than $300. Right now through next Monday you can get it for $270 shipped by entering the promotional code EMCXPWW76 at the checkout, that is very big bang for the buck. It's not the tightest bass or the deepest bass, but it will give you a lot of oomph for your games. If you want sharper, high quality bass that extends deeper than humans can even hear, one of my favorites is the
Hsu VTF3, which is $50 off at the moment, which makes it $750 shipped. If $750 is a bit much for you, another great sub is the
Rythmik FV12r, it doesn't go quite as deep or get as loud as the VTF3, but it does offer lots of high quality bass for $589 shipped. Anyway, as far as subwoofers go, the sky is the limit if the money is there.
One more thing, Monitors are great for everything, music, games, movies, whatever. Anyone who says they aren't good for music either doesn't know what they are talking about or prefers their speakers to mess up the sound. Pit any home audio speaker against an equivalently priced studio monitor, and nine times out of ten (if not more) the monitor will offer measurably higher fidelity sound.
