Halo will never be on a system thay microsoft doesn't own. Halo is their bread and butter, their breadwinner, their shining light that says look here look what we have and you don't. And a good light it is. I'm not sure any developer is stupid enough to take the best first party game you have and put it on a system you can't control and risk people wanting that as much as the origional Therefore taking away sales from you and giving it to them. Halo is a Xbox mover and will be until the system dies. I bought my xbox for halo and panzer dragoon(more panzer really), and everyone I know bought their xbox for halo, that's the only game a lot of xbox owner have (other than the free ones they get with the system.) They might release some other microsoft games on the GBA or even the DS but never will you ever see Halo on any system that doen't have microsoft written on it somewhere, (no the mac doesn't count because they own that too, don't deny the truth)