Hi Jock,
If cost isn't a factor then I would go for the 2TB model. I estimate that your 1000 CDs would probably require about 300GB if ripped in '.flac' format. So the 2TB unit would give you more flexibility when you get used to the B2. For example, if you decided to use 'mirror' mp3 files to play on other non-flac devices then that would require another 100GB at your collection size.
Shawn mentioned possible new features above which is a good case. He mentioned photographs, but the Brennan can store and process photos already, although it is not widely publicised. I have a few thousand photos stored on my B2.
@Shawn; if you want to see the photo section type in '<yourB2IPaddress>/jbv.html' and you will see a mainly blank web page. But you can easily upload photos to the B2 using the menus provided.
Attached is a screenshot from my B2 photo store. (The photograph is of a dog, a young cat and a parrot playing together in Zimbabwe).
Regards,
Peter.