I'll be taking a 3 month trip starting beginning of may and want a lens for super wide coverage. After the trip the lens could be used for anything from scenery to bmx action shots. I'm shooting a 20D, and have the following lenses: Canon 70-200/4L Tamron 28-75/2.8 Canon 50/1.8 Canon 18-55 stock lens My cousin has a Tokina 10-17 and the shots/colors are pretty awesome. My main options are: Tokina 10-17/3.5-4.5 Tokina 12-24/4 Canon 10-22/3.5-4.5($200 more than the 12-24, i dont know if the performance will match that) Sigma 10-20 Tamron 11-18 Any suggestions? Thanks!