I'm done chasing the proverbial audio perfection too. I'm now interested in adding a BIT-20, the IAD card to my BDP-2, and perhaps upgrading my BDA-2 to a BDA-3. I just figured if the USB sounded as good as the AES/EBU on a BDA-3, I might use JUST the USB.
After that, I might consider sending my 4B-SST2 and 6B-SST2 in for the cubed upgrades.
The other thing I've given some consideration to spending money on is Roon and/or JRiver (or some such audio software) that will increase the user-friendly aspect. If Roon ends up working and Roon eventually integrates other popular streaming services (Pandora, Spotify, etc), I could get rid of my Sonos equipment (which I keep only for the convenience of the interface). That'd really be my FIRST priority. Ease of use makes a huge difference!