Couple notes...
Wii, by NPD USA, is at 7.34 million in the USA in in its 14th month of recorded sales.
Despite the shortages, it continues to outpace PS2 by just over one month in the USA according to some research I just did in aligning the launches. PS2 hit about 7.2 million in 15 months. The comparison is fair as well - as at month 14/15 both consoles had two holidays, with the first being the launch holiday.
Xbox 360 by NPD USA is at ~9.1 million in the USA in 26 months of recorded sales. That is about 30% faster then when Xbox reached the same amount, despite higher pricing and the RROD issues according to my research. If 360 ends up with sales 30% greater than Xbox, even over the same truncated time frame (4.5 years vs. the 5.5 to 6.5 years for most consoles) then Xbox 360 will have N64 like numbers in the USA, and similar worldwide totals at least (a bit north of 30 million minimum). As Xbox 360 becomes cheaper though, I imagine the system will outpace Xbox 360 faster.
PS3 by NPD USA is at ~3.245 million in its 14th month of recorded sales. That puts it below both Gamecube and Xbox in the USA according to my research. Interestingly, it had a nearly identical November to Xbox and GC in November number 2, but was ahead of GC and behind Xbox in December number 2.
As a rough guess for what NPD will report in January (four weeks) at this point I'd go with 360k-400k for Wii (supply), 220-260k for Xbox 360, and PS3 110k to 150k. All consoles will be down from last year for the month, with PS3 still too expensive, Xbox 360 past its third Christmas, and Nintendo forced to divert huge supply to Japan for January to meet big demand from games and holidays (Wii Fit, Galaxy, and Brawl). Brawl currently has ~600k+ preorders (not an official figure - my estimate) if the normal extrapolation factors from the prelim data are to believed (I'm a bit skeptical), but it should easily be the biggest debuting game in Japan for Wii since launch (at least 400k, I'd guess 700k - the preorders are literally four times higher in the sample data than Galaxy preorders ever were).