So, I'm really into the idea of buying songs into the rock band network, and so far I've bought over 80 songs, but finding bands I like is a pain, and the in game suggestions don't work either, so what I propose is a sort of filter, that compares rock band network artists to my last fm library of artists and offers content based on what the two have in common. Its rather simple really and should be doable since the xbox has last.fm integration.
Of course actual in game integration may be a bit far fetched so at least a web based rss feed that lets me know when new content reaches that matches stuff in my last profile would be amazing. I do check a wikipedia page for easier browsing of new stuff, but this may be much more convenient for when i add new stuff to my last library that may already be here. This integration could help boost your dlc sales, since I have many friends who use last that dont know of all the new content you guys put in.