Man, I remember in Crystal, my best Pokemon was my level 72 Pidgeot named Sky....
Ability: Does it really matter? They're all relatively useless >.>
Item: Heat Rock/Damp Rock/Generic Item
Nature: Modest (+SpA, -Atk)
EVs: 252 SpA/252 Spd/4 HP
-Rain Dance/Sunny Day
Pidgeot can use both Rain Dance and Sunny Day, and has moves that can benefit, so why not? Rain Dance is a little more beneficial, because it gives Hurricane 100% accuracy. HP Water also gets a boost from the rain. Uproar is for a Normal STAB. Sunny Day is also usable, powering up the already powerful Heat Wave. However, sun drops Hurricane's accuracy to 50%, so you may want to go with Air Slash or something if you want a Flying STAB.