Need some help picking out components for computer audio

I have been lurking on these forums for about a month now, after being referred here by a friend. Curse said friend for ever letting me listen to his setup, made me realize mine sounded like crap and now I have to spend money. Anyway, I have spent most of that month doing research on what would be the best setup for me with computer audio. I should probably explain what my needs / situation is, so I'll do that next.

I do a lot of gaming. I spend most of my free time playing games and listening to music. Most of the games I play don't require positional audio, but I still do occasionally play FPS games so I would prefer not to sacrifice positional audio if I can avoid it. However, for the games that don't require positional audio I usually listen to music during them and so I am perfectly open to using two separate setups (like on-board audio for games and a USB DAC + amp for music). I plan on purchasing a pair of AD700s and having a friend mod a mic into them, similar to what WayTooCrazy did here. I need a mic input, but I already have a good enough one on my on-board sound card, so I can just use that if needed be. I can also have my friend make an extension for the mic lead for my headphone cable, so the mic and headphone jacks don't need to be right next to each other. My budget is $150 - $200, but that can be fudged some if needed be. I can also buy things in stages if there are multiple parts, so treat the $200 as a rather flexible line. ;D

I have a decent motherboard, so I checked to see whether or not the on-board audio was good enough. It uses a Realtek ALC892, which is apparently decent, but not audiophile quality so I'm looking to replace it. Now, from what I have gathered on here what I should do is one of the following:

1) All-in-One Solution #1

Buy a sound card from either the ASUS Xonar series or Creative X-Fi series since I can't use a USB DAC due to losing out on Dolby positional audio. This is assuming I don't get the Astro Mixamp, which I hear isn't so great for music.

2) All-in-One Solution #2

Buy a sound card to use as a DAC and pair it with an external amp, like say ASUS Xonar DG + Fiio E9.

3) Specific Solution

Buy a USB DAC and an amp, like the Fiio E9 + E7 or just the Fiio E10. Use the built-in sound card for games that need positional audio and use the DAC + amp config for everything else.

The reason I am looking at two separate "All-in-One" solutions is because I have heard that it is a good idea to put an amp between the sound card and the headphones. If someone could verify whether or not this is a good idea I would appreciate it. I guess my biggest question is if there would be a big difference between using one of the "All-in-One" solutions or using the specific setup.

EDIT: Also, is there any difference between the ASUS Xonar "X" cards and their normal brethren (STX vs ST, DX vs D1, etc) aside from their interface type (PCI-E x1 vs PCI)?

EDIT 2: I should also mention that I use speakers quite a bit, so if it is possible to attach those to the high-end audio system that would be awesome. They are a good 2.1 set that has rather clear audio quality, so I would prefer not to be stuck with them on the on-board sound card.