To me, sales dont really matter much, just because it sells more does not mean it is better. Probably the main factor in the Wii's success is its price point, so just because it sells more does not mean its the more enjoyable console, the 360 lots of games but plagued with hardware problems, PS3 Blu-ray compatible but high price and not as many games.
Anyways, in sales, I'd say the Wii and PS3 will be pretty close at the end of the generation. I expect Wii sales to drop dramatically by the end of this year or next, people will begin to realize what a rip off it is when they purchase a HDTV, with that being said I expect PS3 sales to take off once HD DVD dies seeing as it plays Blu-rays and plays games in High Definition. I foresee a slow death of sales for the 360 seeing as how its not cheap, and does not have a level of HD-ness comparable to the PS3 (especially since PS3 games are estimated to be only using about 20% of the Cell's potential)
So, PS3 and Wii close for 1st, 360 last.
