too much or to little? Please help!

I hve been reading away on this board, and it only seems to make me more confused, so I'm appealing for some help. I've done my homework, I think.

I'm looking to put a small touchscreen in my living room to basically do the following:

1) play all my music through my stereo
2) light web browsing (google & youtbe)
3) watch tv

Since the screen I'm looking at is only 12", I will not be watching any HD movies, and do not really need an optical drive, etc.

I was going to buy the following:

zotac ion-itx-D wi-fi atom n330 ($129)
case: m350 ($40)
memory: 2gb ($35)
HD: 120 gb 2.5" ($40)
monitor: chinavision 12" touhscreen

Then to watch tv, I was going to add one of those USB tv tuner cards.

My question is that when I total this up and add shipping, I'm looking at approx. $450 which is a little more than I wanted to spend on this.

All my music and files are on a windows home server, so I may not need a HD, can I just use a usb stick? Also, unfortunately where this will be going, there's no lan port, so I needed wi-fi, and that was the cheapest board I could find with wi-fi on it, but perhaps there's a better/cheaper board, and I can just add a wi-fi card myself?

This is going to be out in the open, and I plan on leaving it on all the time, so the quieter and cooler it is, the better.

any suggestions are greatly appreciated, thanks!