Based on the latest Famitsu hardware numbers...
PSP comparisons: After 199 weeks, PSP is where PS2 was after 148.3 weeks (December 31, 2002), where DS was after 89.4 weeks (August 16, 2006), and where GBA was after 126.9 weeks (August 23, 2003).
X360 comparisons: After 147 weeks, X360 is where GCN was after 14.7 weeks (December 20, 2001), where PS3 was after 16.9 weeks (March 3, 2007), and where Wii was after 3.8 weeks (December 22, 2006).
PS3 comparisons: After 99 weeks, PS3 is where PS2 was after 21.7 weeks (July 28, 2000), where PSP was after 53.5 weeks (December 14, 2005), where GCN was after 102.1 weeks (August 24, 2003), and where Wii was after 23.8 weeks (May 11, 2007).
Wii comparisons: After 96 weeks, Wii is where GBA was after 89.9 weeks (December 7, 2002), where DS was after 70.3 weeks (April 4, 2006), where PS2 was after 98.3 weeks (January 14, 2002), and where PSP was after 154.0 weeks (November 17, 2007).
Based on the latest Media Create hardware numbers...
DS vs PSP: Weekly shares of 61.9 / 38.1 bring total shares to 69.4 / 30.6. If DS stopped selling and PSP continued at this week's rate, it would catch up in 505.6 weeks (June 15, 2018).
X360 vs PS3: Weekly shares of 53.4 / 46.6 bring total shares to 23.2 / 76.8. At this week's rates X360 catches up in 1,565.6 weeks (October 8, 2038). If PS3 stopped selling and X360 continued at this week's rate, it would catch up in 196.7 weeks (July 13, 2012).
PS3 vs Wii: Weekly shares of 22.2 / 77.8 bring total shares to 25.4 / 74.6. If Wii stopped selling and PS3 continued at this week's rate, it would catch up in 622.3 weeks (September 9, 2020).
Week over week, most things are flat or down a little. DS dips the most. I presume it's largely due to the DSi announcement, but DSi was only known about for about half the week, so that's a pretty harsh effect. Perhaps next week DS and PSP will have similar numbers again at a lower tier, before their new models appear.
40 weeks into 2008, X360 passes its 2006 total. 2008 is now X360's second-best year, and compared to last year at this time is 45K ahead.
Famitsu Software Stuff
There are a few new games that could be worth looking at, but they'll be better to compare with past titles after another week or two of sales.