But C# is not a deadend. With xna you can put out games for 360, Zune, Windows, and Windows Phone.
True, but I wasn't talking about C# or XNA, but XBLIG specifically. PC's and phones are much more ubiquitous than XBOX, which is the main reason I see them as having priority. Everyone has a computer, so exporting to various OS runtimes should take precedence. And there are a lot more smart-phone owners out there than there are 360 owners, so phone support of some kind would come in second. And don't get me wrong, I think console porting would be a good option, I just don't think the need is anywhere near as big as for OS and phone support.
Also, for every 360 owner that does buy an XBLIG game, there are even more who don't. People generally get a 360 in order to play triple-A titles. Phones, on the other hand, are a different animal entirely. People are more accepting of smaller, simpler games on their phone. Plus the portable nature means more opportunity to buy and play games. People are much more likely to drop $3 on Generic Stick Figure Zombie Arena Shooter on their phone when they can play it on their lunch breaks or on the toilet or whatever, but not so much when you can only play it on your couch on a system that you could be playing Halo: Reach or Red Dead Redemption on instead.
But as far as top priority goes, I still think Mac/Linux support is where it's at. The most common complaint I see from the indie community is "well this game looks neat but it's Windows only so I can't play it *frowny face*." More OS support would be a big draw for indie devs.
-Consoles are so widespread according to some news, it is a broader market possibility!
I really don't think that's true. If you have a source on this I'd be happy to get schooled though . And anyway, as time goes on smart phones will become even more prevalent, and console owners still won't be able to carry their consoles around and play them.