It's logical to blame the economy, but take a closer look.
Hardware bought in 4 weeks September 2008 (revenue is found by U.S price timed by 1.4 to calculate for Euro vs dollar):
Wii: 1145K - 400M dollars
Ps3: 486K - 238M dollars
X360: 647K - 181M dollars
PsP: 600K - 143M dollars
DS: 1586K - 288M dollars
Ps2: 337K - 47M dollars
Total: 4801K - 1.297B dollars
Last 4 weeks of August:
Wii: 1155K - 404M
Ps3: 576K - 282M
X360: 448K - 125M
PsP: 780K - 186M
DS: 1825K - 332M
Ps2: 397K - 55M
Total: 5181K - 1.384B dollars
So it's less than 10% down month over month for hardware.
What you could have done, is that by looking at those, the last week only shows Others data. Maybe that is where you mixed up.
(And holy crap, people spend almost 4B dollars each quarter, out of christmas, on hardware alone?)
Now, Software
September (same 4 weeks):
Wii: 5.2M - 328M
Ps3: 3.2M - 268.8M
X360: 4.6M - 386.4M
PsP: 1.0M - 42M
DS: 7.1M - 298M
Total: 21.1M - 1.323B
August:
Wii: 5.8M - 365M
Ps3: 2.9M - 244M
X360: 3.9M - 328M
PsP: 1.3M - 54.6M
DS: 6.2M - 260.4M
Total: 20.1M - 1252B
So there was a slightly higher revenue in September for software. And overall, it rules out. The reason revenue is important here, is that it is how much money people spend.
http://www.vgchartz.com/games/userreviewdisp.php?id=261
That is VGChartz LONGEST review. And it's NOT Cute Kitten DS