All but ready to order... a few last questions

Budget: $1200-1700
Expectations: Moderate gaming (little or none online), home video editing, playing blue-ray videos on LCD TV. I expect a PC to give me good performance for 5+ years (though I may upgrade the video card during that time).
Usage: Playing Crysis, GTA (all), Thief, etc.; Playing blue-rays, movie files; editing home movies; serving as the home media and data center. (Note that I already have external drives for media/data files. Internal storage will be for OS, apps, and frequently accessed files. So mucho HDD size is only a convenience, not a necessity.)
Special Needs: Space is tight and I live in a dusty old house. Can't really avoid putting this in a computer armoire b/c it's in the family room. Sawed a hole in the back of the PC slot and the doors are left open while the PC is in use. Good case airflow/fans and dust filters are needed.
Saved Ticket #: 678001

Specifications:
Chassis Model: Special Deal Hot Seller - Corsair Carbide 300R
Exterior Finish: - Standard Factory Finish
Trim Accents: - Standard Factory Finish
Processor: Intel Core i5 2500K 3.30GHz (Unlocked CPU for Extreme Overclocking) (Quad Core)
Motherboard: ASUS P8Z68-M PRO (Intel Z68 Chipset) (Features Intel Quick Sync Technology) <b></b>
System Memory: 8GB DDR3 1600MHz Digital Storm Certified Performance Series (Highly Recommended) (Hand Tested)
Power Supply: 600W Corsair GS <b></b>
Hard Drive Set 1: Operating System: 1x (120GB Solid State (By: Corsair) (Model: Force GT Series CSSD-F120GBGT-BK) (SATA 6Gbps) <b></b>
Hard Drive Set 2: Multimedia\Data: 1x (500GB Seagate Barracuda (7200 RPM) (16MB Cache) <b></b>
Optical Drive 1: Blu-Ray & DVD Writer/Reader (Burn + Play Blu-Ray & DVDs) (12x BD-R) <b></b>
Optical Drive 2: - No Thanks
Internet Access: High Speed Network Port (Supports High-Speed Cable / DSL / Network Connections)
Video Card: 1x NVIDIA GeForce GTX 560 Ti 1GB (PhysX Technology) (Overclocked EVGA 01G-P3-1563-BR) <b></b>
Add-on Card: - No Thanks
Sound Card: Integrated Motherboard Audio
Extreme Cooling: AIR: Stage 2: Corsair A70 Dual 120mm Fans High Performance Cooler <b></b>
Chassis Airflow: Standard Factory Chassis Fans
Boost Processor: Stage 1: Overclock CPU 4.0GHz to 4.4GHz
Windows OS: Microsoft Windows 7 Professional (64-Bit Edition) <b></b>
Recovery Tools: Windows Recovery Toolkit (Bundled with Windows 7 CD)
Exclusive T-Shirt: FREE: Digital Storm T-Shirt - Black (Medium)

Hi all. I posted a build a week or so ago and have done a bit more research and think I've now ready to buy. This is my first custom build and I'm no computer expert so have a few more questions I'm hoping for help with. (And maybe just a little peek over the shoulder from someone who knows better what they're talking about.)

1. I settled on the P8Z68-M PRO mobo (over similarly priced options) largely because it has USB 3.0 on the back panel, eSATA, and DisplayPort. These features seem more future proof than what the P8Z77-V LX supports, e.g., eSATA for an external backup drive. Also I am kind of hoping some day to hook up home speakers to this (or to a receiver) so thought the 6 audio ports might be more useful than 3, but that's just a guess.

I expect this machine to last 5-7 years so do worry about future-proofing. I liked the Sabertooth Z77, but was trying to save $$. Will I regret not boosting for the Sabertooth? Or getting the additional USB3/PCIe options of the -V LX? I don't plan on SLI and don't think I'll need more PCIe slots than the -M PRO has. (All I can think I might add in future is another optical drive, possibly another hard drive, maybe a wireless card. I'll upgrade the GPU but will likely always stick with single card. I would think the SATA options and remaining PCIex16 and 2xPCI will serve just fine.) But maybe I'm missing something?

2. I have here the default Epoch case (Corsair Carbide 300R), which I had originally chosen for (a) small size and (b) for its front-mounted USB 3.0 ports. But since the mobo I'm looking at only has 2 (rear) USB 3.0 ports, I'm thinking that the 3.0 front ports on this case are an irrelevant upgrade for me. Is that right? If so, my other options (given my size limitations) which might save a couple of bucks are the Cooler Master Elite 430 (even smaller) or the AeroCool AeroEngine Plus. Both look fine but maybe you know if one promotes better front-to-rear airflow (to push air out of the armoir).

3. I think the 600W power and AIR2 options are plenty. Please correct me if you think that's foolish.

4. And finally, a possibly totally idiotic question about USB (2.0) ports on the mobo. If a mobo has 14 USB connectors, and the back panel has 4 USB 2.0 and the case front has 2 USB 2.0, what use are the remaining 8 connectors on the mobo good for? It seems most every mobo I looked at had way more USB connectors than I typically find on a PC, and I don't think internal components are usually connected via USB, though I may be dead wrong about that. Anyway, is there an easy way to expose those externally? I'm always short of USB ports (even after I bought a 6-port hub) and it seems silly I can't take advantage of what's already on my board.