Based on the latest Famitsu hardware numbers...
PSP comparisons: After 241 weeks, PSP is where PS2 was at 194.3 weeks (November 18, 2003), where DS was at 103.1 weeks (November 20, 2006), and where GBA was at 162.5 weeks (April 29, 2004).
X360 comparisons: After 189 weeks, X360 is where GCN was at 17.7 weeks (January 11, 2002), where PS3 was at 39.3 weeks (August 7, 2007), and where Wii was at 5.7 weeks (January 5, 2007).
PS3 comparisons: After 141 weeks, PS3 is where PS2 was at 47.3 weeks (January 23, 2001), where PSP was at 70.1 weeks (April 10, 2006), where GCN was at 130.7 weeks (March 12, 2004), and where Wii was at 36.3 weeks (August 7, 2007).
Wii comparisons: After 138 weeks, Wii is where GBA was at 99.7 weeks (February 14, 2003), where DS was at 77.5 weeks (May 24, 2006), where PS2 was at 118.2 weeks (June 3, 2002), and where PSP was at 168.9 weeks (March 1, 2008).
DSi comparisons: After 38 weeks, DSi is where GBASP was at 52.3 weeks (February 10, 2004) and where DSL was at 19.2 weeks (July 10, 2006).
So DSi has passed what GBASP did in its first full year with 14 weeks to spare. Clearly DSi is a more successful reiteration of hardware than GBASP, but also clearly not the giant DS Lite was.
Based on the latest Media Create hardware numbers...
DS vs PSP: Weekly shares of 75.2 / 24.8 bring total shares to 68.4 / 31.6. If DS stopped selling and PSP continued at this week's rate, it would catch up in 477.9 weeks (September 23, 2018).
X360 vs PS3: Weekly shares of 25.5 / 74.5 bring total shares to 24.8 / 75.2. If PS3 stopped selling and X360 continued at this week's rate, it would catch up in 706.8 weeks (February 11, 2023).
PS3 vs Wii: Weekly shares of 27.3 / 72.7 bring total shares to 28.4 / 71.6. If Wii stopped selling and PS3 continued at this week's rate, it would catch up in 549.3 weeks (February 4, 2020).
Week over week, there's no uniformity or real pattern to the ups and down.
Through the first thirty weeks of the year, overall sales are down. However, the systems can be split into camps of 3 up and 3 down. Here's how the year-to-date year-over-year percents stand as of now.
Home hardware: -39.4%
Portable hardware: -21.3%
Sum of all hardware: -28.6%
With YTD sales of 245K by Media Create, X360 could stop now and still have its second best year yet. #1 is 2008 at 322K.
Famitsu Software Stuff
In its second week Dragon Quest IX continues outpacing Dragon Quest VIII, though at 2.95 million it narrowly misses 3 million. Though not pictured here, it's worth noting that through week two Dragon Quest VII was at 2.93 million.
After its first week, Dragon Quest IX became the DS's #8 title. After its second week, it is #7, passing Pokémon Platinum. Everything else is currently at 3.4-5.7 million, so further passing will be slow-going.
PSP's Ys I & II Chronicles starts off well, matching the better two PS2 Ys starts. I'm not finding any other Ys games in Garaph. I specifically looked for the DS release of I & II, but it appears so far that has only released in North America.
In some sort of sales turkey, Momotarou Dentetsu 20th Anniversary has ranked #30 for three weeks in a row.