People are thinking this gen will end way to early. Computer technology isn't moving as fast as it has in the past, and is definitely not going to be at a price to be feasible to release a new console at by 2012. Factor in the huge investments / losses made earlier this gen and neither Microsoft or Sony will be keen to start another gen too soon.
I reckon Wii HD will hit around 2012 but Sony and Microsoft will hold off for a few more years. We've still got to see the next handhelds before thinking about consoles too.
But yeah, I'd say around 60m - 70m LTD. It's nearly outsold the GameCube and isn't priced anywhere near what the mass market can accept. It's got a lot longer to sell those units then previous generations and Sony will most likely start taking alot from the expanded market in 2-3 years when (if) Blu-Ray takes off, it's at a mass market price, HD uptake is higher and they've got their own brand of casual appeal type software / functions.
PS3 was released 2 years earlier then it should have been and most likely would have been.