Change the motherboard to a P5Q-E, CPU to a Q6600, 4Gb of DDR2 800 with 4-4-4-X timings and, most importantly, the soundcard away from your current choice.
In order of recommendation...
The P5Q-E is an excellent choice for a midrange build.
Good cooling, features, layout and overclocking.
Plus, you can use the much cheaper DDR2 RAM over DDR3.
Both CPU's you listed are excellent choices.
Plenty of power but limited to 2 cores.
As you are planing on doing some recording, which will entail loads of remixing and encoding, a quad core will give you better performance with most multi threaded software packages.
On top of that, it can be overclocked to the same 3.0Ghz ridiculously easily even with the stock cooler and voltages.
Anything above DDR2 800 4-4-4-X is a waste of cash.
You will see little to no performance increase going with any faster current standard.
What matters most right now is the volume of RAM.
4Gb should give you plenty to play with right now and if you decide you need more while remixing your music, you can always up it to 8Gb.
The X-Fi Xtreme audio is a terrible card and you should not purchase it!!
It does not even have a X-Fi chip powering it, merely a rebranded Audigy SE chip.
From the
Wiki Page.
X-Fi Xtreme Audio
The entry-level model of the X-Fi series, the Sound Blaster X-Fi Xtreme Audio, does not actually have the EMU20K1 chip but is a re-branded Audigy SE, using the same family of chips (CA0106-WBTLF), and even the same drivers.[14] Thus, not only is all of the X-Fi–related processing performed in software, but it also lacks basic hardware acceleration just like the SB Live! 24-bit, the Audigy SE and other budget Soundblaster models. The X-Fi Xtreme Audio does not use the same drivers as the rest of the X-Fi family, some games do not recognize it as being "X-Fi capable hardware", and the device's hardware profile resembles that of older Live! and Audigy cards.
Furthermore, users have reported that it slows down some applications and games, and that rear sound in games (all) is muffled and of profoundly low quality.[15][16][17] Thus, even if the card is marketed as part of the X-Fi line, it does not belong to it technically, just like the Audigy SE doesn't technically belong to the Sound Blaster Audigy series. The card is not marketed as supporting the "X-Fi Gaming Mode" (but is still marketed as "X-Fi"), and there are no official implicit or explicit statements regarding its having hardware acceleration or not.
If you want a
real sound card, get an ASUS Xonar 2 based card.
Everything I have heard about them is that they are top end cards.
I would agree that your video card choice is a little low end.
It will probably be fine for what you are looking to do but if you can afford it get a 8800GT or 4850 for a good performance boost.