server vs nas

Dedicated NAS (Network Attached Storage) Unit or just setup RAID-1 in my PC?
I'm looking at NAS units and think the D-Link DNS-323 is perfect for my needs - RAID-1, UPnP streaming to my XBox, BitTorrent client for overnight downloads, print server, etc...
But, is there any benefit to that vs. just getting a RAID card and leaving my PC on 24/7? Obviously the NAS will use less electricity and probably be quieter, but from a functionality standpoint will it make a difference?
Let me introduce alternative 3. It's what I did.
I get a lot of old outdated systems to cart off to the junk yard, so this didn't cost me much. Your mileage may vary.
I carefully selected one of the "very outdated" systems to use as a Dedicated File Server on my network. It has an AMD Athlon XP 2800+ processor. My major reasons for selecting this particular system was that the motherboard has a Gigabit Ethernet and a RAID controller built in. I put a very inexpensive ($9) 128M AGP video card into it. I put 512M of RAM into it. I installed Fedora 8 64 bit edition and setup SAMBA. I also installed XP Pro SP3 on a separate partition so that I can boot to either OS. I have a 40G drive for the OSs. I have two 500G drives in RAID-1 for the storage partition.
The system runs quiet. It sips the electricity (150W peak useage). I don't have any speed issues with how fast I can transfer data to or from the system over the network. I have CAT6 to the router for now.
[phpzon]server vs nas, 5, Electronics[/phpzon]
[phpbay]server vs nas, 30, "11211"[/phpbay]
NAS-/Media-Server im Eigenbau - Teil 1