I am about to buy a new computer and wanted to know the forum's opinion on the utility of a couple of components for optimized game play with a heavily modded FCOM Oblivion install. I am not trying to buy the best gaming machine on the market, but want to get a really good work horse computer that will also let me play Oblivion the way I want to with whatever texture or graphics improvements mods I like without having to suffer a performance hit. (I will want to use this same machine for Skyrim - but I have not even looked at that game's requirements yet.) Any feedback would be appreciated.

Base System:
Dell XPS 8500
Intel i7-3770 processor
Blu-ray combo drive
Bose Companion 2 Speakers
Logitech MX 550 cordless mouse & keyboard
2TB 7200 RPM SATA Hard Drive 6.0 Gb/s

1. OS - Is there any utility in getting Windows 8 Pro vs the standard Windows 8?

2. Ram - I know more is always better, but is 16GB of dual channel DDR3 at 1600 MHz good enough? Put differently, am I likely to see any noticeable game performance increase with 24GB over the 16?

3. Sound card - In older computers, it was a good idea to have a stand alone sound card to reduce the work load from the main system, but is that still necessary? The computer I am looking at comes with integrated 7.1 with WaveMAXX 4 onboard card. I am tempted to get another stand alone Sound Blaster card, but am willing to forego it if it no longer has much impact on game performance.

4. Video Card - The Dell comes with an NVidia GeForce GT 640 1 GB GDDR5 for Win 8. Is this sufficient for Oblivion's best graphics mods or do I need a second card. (My current computer has two NVidea GeForce 9800 GT w/512MB cards).

Thanks again