Oh man it was hard for me to pick which Pokemon to use for fly. When I play Diamond and Platinum I use four main Pokemon and train them more than the last two spots, so I have a choice of two extra Pokemon, usually for HMs. First time around it was Staraptor and he served pretty well in battle so he had two sides for use. Then there's Noctowl and Honchcrow who I used different times during the games. Now, even through X and Y I make sure I have a Drifblim. I love that Pokemon so much, and it will always have a special place on my team, even if it's not so strong. (Which it's usually not)