I don't know when was the last time Nexgenwars was updated. VGChartz is the "most" reliable as it is updated weekly. However, there is still question about its accuracy. But lets face it, VG is far more open than NPD, though if I was going to put money on either, it will be NPD, simply because they are reputable. If the industry accepts VG as a legitimate source for sales data, then things will be different.
Concerning sales though, are the sales figures provided by Sony sales to retailers or actual sales of a console.
http://www.scei.co.jp/corporate/data/bizdataps3_sale_e.html
EDIT: I will say however, VG is THE best place to go to for international sales of games and consoles. The trend is shifting, more and more people are accepting VG as a reputable and legitimate source for sales. Partly because there is an open discussion on the site.
2011 Predictions
Wii: 17m (100 million total)
360: 13m (63 million total)
PS3: 15m (61 million total)







