Wouldn't basic logic suggest January of '07? I wouldn't expect any less,
considering Defender itself is an integral part of Vista's malware
protection; and that if we saw Defender being released prior to Vista's
RTM, then why not the other components such as WinFX and IE 7 (all three
of which will be back-ported to XP). Why not? Becuase they won't be ready,
is the chief factor, and even if they were, it'd make Vista seem old by
Jan. of '07.
Besides, how long was Beta 1 of Defender (formerly MS Anti-Spyware) around
for anyways? Something like a year, if not more...