Current Franchise sales sit at 26.12 million, though it is growing with Halo 3 and Halo Wars still selling, What will Reach and ODST add? Will we see Halo 4 this Gen?

ODST - 4-6Million somewhere in that range.
Reach - Absolutely no idea. Id take a wild guess at 6-7Million

40 Million + for sure, 50 million if Halo 4 comes out

I won't mention the fact that Halo 1 is still selling on XBL

^ Figures can't be counted though, if Microsoft ever release figures it could help though ^^

There is no more halo 4 guys bungie already announced it. You won't see halo 4 EVER. Only think you have to look forward to is the release of Halo 3 on PC.

Halo 3 may be overtracked btw...

Microsoft owns Halo and has assembled a new studio specifically to make Halo games, so Bungie really has no say in it.

Halo 3 on PC would surprise me, since GFW Live is free. Would be a foolish move on MS's part, IMO.

ODST will sell 5 million units.

Microsoft have been very low key in Halo 3 sales, it was like 8.1 million January 08, that was nearly 2 years ago