Looks quite good to me. A few suggestions:
Doesn't the Asus board already have onboard sound? I'm not really familiar with Intel Pentium boards. If so, I hear tell the sound on Asus boards is of good quality and should be enough for you without adding a sound card.
You've listed PSU twice I think, the Antec 480 should do the job just fine.
Looking at the computer's uses and taking into account your budget, perhaps consider the ATI Radeon 9800 Pro All In Wonder? Best of both worlds, gaming & creativity both catered for. Also, you wouldn't need the TV Tuner card with the AIW, it has a Tuner built in.
For a little extra, perhaps consider the Pioneer A106 DVDRW, it's dual standard, The A05 only copes with -R.
As far as I know, all Corsair memory comes with heat spreaders.
As I mentioned, only suggestions, it's looking like a very good system indeed