Hai guys. Newbies here. Need help from experts.

I need serious recommendation since Diablo3 coming out LOL.
I like COSMOS II casing. Good to have?

Target to get reliable casing (Anti Heat System) :
- Black casing all around including interior.
- A good airflow
- Dust filter
- Smart and Neat Cable Management
- Watercooling compliant
- Temperature Measurements system
- Etc

Purpose
- Games
- 24 hours download
- Store Lots2 of 1080p movies (Need like 10 terabyte hdd)
- Link to my Led Tv
- Graphic work
- Mics work

Pc Specs still puzzle on what to choose =(

Any help or advise will be appreciated. Thank you in advance you guys =)

Budget around RM1k to RM2k just for a good cooling system and dust free
Thanks bro for highlighting the matter

Just need to know what's the high end for the current cooling system. From there, cam work out my budget range