Wind is certainly the best of the renewables; however it suffers from its lack of predictability. I live in TX where there is more wind systems than anywhere else making somewhere between 5-10% of the total power in the state. We've had a couple of incidents where a combination of light winds and lack of sufficient conventional power capacity led to a near shutdown of the state's power grid.
This is leading some to think that in addition to the cost of the wind generators, some investment in backup systems is also needed thus driving up its cost.
I've seen other comparisons showing wind as more expensive than gas/coal.
I do have to question the accuracy of the cost comparisons. The wiki referenced shows wind power at $97/MW and coal at $95.
The reason I question this is because the average wholesale price of power on the Texas grid for 2010 was about $40 / MW; I don't think the power companies are engaging in a money losing biz.
http://www.ferc.gov/market-oversight/mkt-electric/texas/elec-tx-yr-pr.pdf
Seneca
