You should download the manuals for both the 450x2..and the pci-e..becuase you may prefer buying a bundle (450x2-drive-pci.e) once you see how fiddly things get with a 450x2.
If you have no intention of using wi-fi...pci-e has issues..you can't turn it off!
I was planning on buying the Wifi Dongle. Saw that installing pci-e was a bit hard. I know the speed will be lower, however I mostly download xvid movies (around 1/2 GB per movie). I figured/hope that the dongle will be fast enough for me to transfer my movies. I also will place the player in a closet (?) under the TV (I'm Dutch, don't know the good word for such a piece of furniture...), so i'm not sure if an antenna will work inside it.
I had a thought..you should be able to get at hfs+ hosted files via upnp..even on a PC.
After I get my mede8er tomorrow (probably) I'm going to figure out how this works
First i still need to decide if i'm going for the 500 or the 450 Update:
Going for the 450X2. Figured that 1 TB is enough for me, so then I rather have a smaller one as the specs are the same between the 450 and the 500