A lot of audio-lovers use Macs -- those of us that were trained on ProTools in the old days, for instance, where often using Macs for audio work even when we had PCs at home... So I think there could be a decent Apple/Mac audience out there for that would love the JRiver Media Center... if you could get them to give up the slick-looking and free iTunes....
Although I'm primarily a Windows guy, I'd like to see JRiver offer a Mac-installer for their Media Center due to three reasons: One of the computers in my house is a new Macbook Pro; one of my computers at my work is a desktop Mac; and 50% of my friends in NYC are now on Macs .... I'd love to run my Mac-loving friends into JRiver MC users, and for those few hours a week when I have to use a Mac, it'd be swell to have MC running instead of iTunes, but I'm not gonna pay $150 for an extra copy of the Windows OS along with $80 for Parallels/Bootcamp/Etc. for the privilege...
Well, I would if I had the cash, but in the meantime....
Actually, if JRiver were to hop on the AJAX train and develop it's own (open source?) web-based Media Center -- a la the "Songbird" program but with the full power of MC -- that'd solve the problem, wouldn't it? We'd be able to hop onto MC from any computer anywhere... Of course, they'd need to figure out a profit-model to go along with it, but it seems like this is a future (Firefox, Gmail, Google Documents, Songbird...).... should get on it....!