1) I assume you've investigated the UPLOAD bandwidth requirement and have a suitable plan to support this.
Not sure of what Ethernet solution you'd need but it's possible a good PCIe card might be required rather than onboard.
2) Also, have you looked at using SHADOWPLAY for any of your HD streaming?
3) It's also difficult to give better advice as you don't specify how MANY PEOPLE will be using this system at a time.
If it's only a few people this system might be complete overkill.
4) It's also not clear exactly HOW you are using all the drives. I get it's in RAID, but specifically WHAT are you doing in terms of HD transcoding etc? Again, it may be complete overkill but it's not clear what exactly you're doing so it's hard to comment.
1. I'm good there. I'll look into a pcie card.
2. Never heard of it, I'll google it.
3. Up to 4 remote clients. Ill be running a few game servers with 4 clients. I'll want the extra power for any future services i may run.
4. I'll be using the drives in raid 5(still need to find a good raid card). Most of my media is 720p.