Based on the latest Famitsu hardware numbers...
PSP comparisons: After 219 weeks, PSP is where PS2 was at 171.1 weeks (June 9, 2003), where DS was at 97.1 weeks (October 9, 2006), and where GBA was at 147.7 weeks (January 16, 2004).
X360 comparisons: After 167 weeks, X360 is where GCN was at 16.0 weeks (December 30, 2001), where PS3 was at 29.5 weeks (May 30, 2007), and where Wii was at 4.7 weeks (December 29, 2006).
PS3 comparisons: After 119 weeks, PS3 is where PS2 was at 33.6 weeks (October 19, 2000), where PSP was at 58.3 weeks (January 17, 2006), where GCN was at 119.0 weeks (December 21, 2003), and where Wii was at 31.1 weeks (July 2, 2007).
You may notice PS3 and GCN are both at 119 weeks. The streams haven't crossed quite yet, though. Usually one decimal is plenty enough, but in a case where things are so close it doesn't cut it. Through 119 weeks PS3 is still about 4400 units ahead of GCN.
Wii comparisons: After 116 weeks, Wii is where GBA was at 93.8 weeks (January 4, 2003), where DS was at 75.3 weeks (May 9, 2006), where PS2 was at 112.0 weeks (April 21, 2002), and where PSP was at 162.4 weeks (January 16, 2008).
DSi comparisons: After 16 weeks, DSi is where GBASP was at 34.5 weeks (October 8, 2003), and where DSL was at 12.3 weeks (May 23, 2006).
Based on the latest Media Create hardware numbers...
DS vs PSP: Weekly shares of 63.7 / 36.3 bring total shares to 68.8 / 31.2. If DS stopped selling and PSP continued at this week's rate, it would catch up in 477.6 weeks (January 4, 2017).
X360 vs PS3: Weekly shares of 61.1 / 38.9 bring total shares to 24.8 / 75.2. At this week's rates, X360 catches up to PS3 in 205.7 weeks (February 1, 2013). If PS3 stopped selling and X360 continued at this week's rate, it would catch up in 74.6 weeks (July 30, 2010).
PS3 vs Wii: Weekly shares of 48.8 / 51.2 bring total shares to 26.6 / 73.4. If Wii stopped selling and PS3 continued at this week's rate, it would catch up in 307.3 weeks (January 14, 2015).
Week over week, you're either down or you're Xbox 360.
This week's 16,973 is the lowest Wii week ever by several thousand units. Its previous low was 20,412; just two weeks ago.
Through the first eight weeks of the year, almost everything is down by some degree. Here's how the year-to-date year-over-year percents stand as of now.
Home hardware: -45.7%
Portable hardware: -22.1%
Sum of all hardware: -32.5%
Famitsu Software Stuff
Mario & Luigi RPG 3 (3432) has a much bigger first week than either of its predecessors. However, it probably can't remain this much ahead. Since it's not a holiday release it probably won't have the huge week 2 of December release Partners in Time (212) or the big weeks 6 & 7 of November release Superstar Saga (1150).
Among my records for releases on PS2-and-later systems, PS3 Street Fighter IV has the best Street Fighter first week, narrowly beating out PS2 launch title Street Fighter EX 3. Of course, if you add in the X360 Street Fighter IV, it becomes a little less narrow. PS3 SF IV also beats out the known totals for all the Street Fighter releases since EX3.