It seems you're really never gonna get better than using a wired connection to your music server (hey, 10/Half isn't all that bad). Other than the occasional dropped song (very rare - 1 in 100 songs or so), my M1001 plays flawlessly.
Our overly industrialized societies are just awash in stray radio signals that we can never truly isolate from devices looking for specific radio frequencies to gather data from. Maybe try installing a lead pipe from your router to your Roku to keep them out?
Case in point: look how many people on this forum say that their "acid test" to see if their Roku is getting a truly uninterrupted wireless signal is to turn on their microwave oven for a few minutes to see if their Roku skips songs. Every electrical appliance in your home is now suspect.
I spent many hours in my hot attic with a 1000' roll of CAT5e plenum cable just to avoid all of the issues I knew would occur using wireless (enough bad experiences at work using wireless convinced me it's an imperfect, unreliable medium at best). For a single PC or laptop, it works well, but when many users or streaming data is being used (both of which require significant bandwidth), they'll eventually overwhelm the access point, especially when there's alot of stray signals for the access point to sift through.
I know some of you don't have the option of running CAT5 in your attic, but if you have the home, the time and the energy, I highly recommend it. Then anything you put on your network will always work at full bandwidth for each device with minimal interference, even if it is 10Mbit - half duplex.