I think the Wii U will be #1 overall this year, for home consoles of course. Just look at some general numbers:
PS3 sold about 12 mil, 360 about 10.5 mil this year, and both are decreasing. In 2011 the PS3 was over 14 mil. I expect in 2013 it will be at 11 mil max, more likely 10 mil. This is without the launch of its successor. If the PS4 launches, PS3 could fall to 9-10 mil or so.
Wii U is currently tracking much higher than PS3 and 360 were at launch; 360 sold 6.8 mil in its first full year, while PS3 sold almost 8 mil in its first full year. It's not unreasonable to expect Wii U to sell over 8 mil in 2013.
Now, the other side of the spectrum: the Wii, which the Wii U is tracking very slightly under, sold 16.5 mil in its first full year. Of course, it's ridiculous to expect the Wii U to keep pace with the Wii this way. However, if it sells midway between the PS3 and Wii did in 2007 (not an outrageous prediction given Wii U launch sales), it will sell about 12 million hardware in 2013. Even if it falls slightly short of that, it still stands a good chance of beating PS3 and 360.
