I own both
I own both. The ONLY reason I have a PS3 is because I use it as a dirt cheap Blu-Ray player. As its easily upgradable, its the best blu-ray player out there. I only have two games for it - the ones that came bundled with it. I have just short of 20 for the 360. The thing is, there’s many people out there who got one for the same reason I have. Add to the fact you can stick Linux on it and therefore it makes a damned cheap computer as well and you have to question how many of those consoles are actually being used primarily as a gaming console.
The only figure I reckon that is worth any value in all of this is the number of titles per machine sold as it gives you a more accurate figure and after all, like printers, the manufacturer makes the money out of the media, not the initial hardware.