I'd like to see some more/better guitar effect apps ported over to Linux as I play bass and need some crazy effects from time to time. I don't care for any specific one whether its Guitar Rig or whatever. Guitar Rig has a mac port so it couldn't be hard for Native Instruments to get it on Linux. I refuse to run it in Wine too because I don't get native asio that way unfortunately.
The second thing I'd like to see is some more games obviously. And then the third one, hmm.. I don't really need anything other than that.
If you want a good set of guitar/bass effects on linux you can test Rakarrack at http://rakarrack.sourceforge.net/ . This app have 10 effects and 80 predefined presets ... someones very crazys...
1. AutoCAD ( since BricsCAD: http://www.bricsys.com failed to deliver a version 7 and 8 for Linux )
2. ETABS/SAP ( that code needs some optimisations badly, it's 20 years old in development, and it feels old too; no 3D acceleration, bad UI )
3. Tekla ( given it's price tag and it's features this could be awesome to port )
these are the apps that keep me on Windows, at job anyway