Help me spend my money

If you are still using your Musical Fidelity V-Link, I would say upgrade to something better. You should hear a big improvement.

Room treatments. Lesson I learned is invest $ there before spending on upgraded equipment. You won't know how good your current equipment can sound until you treat the room. A couple of GIK bass traps behind speakers made a big difference...panels on side walls and wall behind listening space brought incremental improvement. I do listen relatively "near field"...about 7-8' from speakers and room treatment was like an equipment upgrade, in my opinion. Good luck "investing"!

My vote is room treatment. I understand your thoughts about it not being as fun as getting new gear- I felt the same way. However, don't let that fool you. It's a potentially significant upgrade. I stared with Gik tri-traps in the corners then panels for first reflections. Those are good places to start.

If you don't have any sort of room treatment-my vote this this is by far biggest bang for the buck. Bass Traps in the corners and absorbers/diffusors on first reflections a must...let us know what you do!

If you happen to live in Texas, I am about to post a pair of ASC Tower bass traps...

No on the usb cable. No on the converter for now. They become obsolete too fast. Realtraps are great but try before you buy to see if you need them and how many. The Caps server MAY be a great idea, but check out the Auralic Aries coming out soon. This may be a great way to enjoy your music ( or Spotify ) and you are already using the I pad interface and computer audio. A lot more hi rez music available as downloads and the Aries should play them all. We should know soon how well the Aries and Caps server get along. A lot of posts over on Computer Audiophile. I've checked out you system. Let's face it, your and Audiophile and a Music-phile. Best to admit the truth.