I have found through a couple weeks of experimenting with a remote desktop stuff on Linux at work that the best I can come up with is using TigerVNC server with UltraVNC on a Windows desktop.
Mind you this is purely as a end user. I just wanted something that worked the best with the least amount of time and effort I could put into it.. because I did not have much time at all.
The remote system was a Debian VM being set up as a XFCE desktop on a CentOS 6.2 host running on the far side of a large corporate network. I tried out NomachineX, Spice, X windows, and various VNC incarnations. Most VNC stuff pretty much sucked, but running a Xvnc/TigerVNC was impressive. In terms of low latency, visual quality, and things like 'copy-n-paste' working properly it was the best I could find and setup in my limited time.
The RFB protocol is very simple and if Wayland can take advantage of those sorts of optimizations that TigerVNC uses when combined with per-application buffers and proper compositing on local and remote systems... then that would be probably be a huge winner.
If they can combine that with how Spice is able to detect video and compress sections of the display to a streaming codec like MJPEG, then I think that Wayland remote desktop/applications could be a thing of beauty.