The problem with saying that is you end up sneakernetting stuff off other people who DO have HD, you're going to get annoyed when you can't watch it.
Both of those use analog connections to the TV, lowering your quality, and on a digital TV, you'll notice it.
They ARE cheap enough that it might be worth a go, but I'm of the opinion you're better off buying a real deal thing in the first place.
I like the WD TV range, and would suggest the WD TV HD, because the Mini model lacks HDMI: http://pricespy.co.nz/product.php?p=358745
For more future proof, get the Live version for it's network support:
http://pricespy.co.nz/product.php?p=473945
What I like about these is a pretty decent interface, and they fact that they update the firmware to allow for changing codecs. A lot of the other cheap stuff doesn't.