I bought a DNS-321 last year. So far I only use it for cental file storage and for streaming my edited camcorder videos via my PlayStation 3 to HD TV. I read about "Application Packs" and Fun_Plug, but so far have decided to leave well enough alone. I am not a Linux guru and had a frustrating experience getting NSLU2's working as a Web Server and for Music Streaming (Firefly). Once I got them working, I have been afraid to upgrade applications, etc. fearing I might break them.
I see the main difference between the DNS-320 and DNS-325 besides the faster processor and extra memory being "Add-On Applications". I have spent time researching these and am interested in Ajaxplorer and Photo Center (Gallery 2). However, I wonder about the level of support D-Link will provide. I noted that Gallery 3 has been out for some time which makes me wonder why they chose Gallery 2. Will there likely be other 'Applications' made available such as Web Servers and other Music Streaming applications?
Fred