Ummm... The only console to sell more than the original
I did say "device" not "console." The DS just passed the PS2 in total worldwide sales.
A quick Google fails to present any concrete numbers to go with that widespread claim. Everything links back to VGChartz and I somehow doubt Nintendo wouldn't be shouting that sort of figure from the heavens.
Not that I don't expect it to happen at some point mind you, I just don't think anyone can say for certain yet that it has.
I also wonder if that includes the DSi and DSi XL, which introduced new features that weren't available on the previous models. I'm not sure that quite qualifies as all being one pool of sales any more than pooling all of the iPhone sales together, which would in fact make it the #1 "gaming device" ever.
Both of these figures are from the respective Wikipedia pages (under units sold on the side bar) where the footnotes for the figures are straight from Nintendo's and Sony's websites.
Nintendo DS: 153.67 million (as of end of 2012)
Playstation 2: 153.6 million (as of November 2011)
Granted the PS2 figure is a bit out of date, but I can't imagine they've sold much in the last year or so.