Im back and with more knowledge than last time I was here

Im really loving my landscapes but finding the 15-85mm lacks sharpness and scope for the wider shots so im wanting to invest in a wide angle lens but which one?

I would LOVE to get my hands on the Canon 11-24!! But I just dont have $3000.

My question is what is my next best alternative?

The new Tokina 11-20mm has been suggested to me but I want to do my research before buying.

Its for a 7D