Yay, another Deoxys fanMeteor Cave. It's hard to get through, but there is tons of money. It also has my favorite Pokemon.
I forgot Lapis Cave in my fave blue dungeons.My choices are odd: ALL DUNGEONS THAT ARE COLORED BLUE (Stormy Sea, Mt. Freeze, Northwind Field)
I also like dungeons that contain the pokemons in my trainer card. (Frosty Forest, Purity Forest)
When I get bored or when there are no good missions, I go to Tiny Woods and Thunderwave Cave and bump all pokemon there(who annoyingly want to be my friend even if I already have one of them) without any need for PP moves.
I also like Sky Tower because of the cute, fluffy clouds.
For training, I use Magma Cavern and Fiery Field. (Fire pokemon, begone from the power of my Swampert!!! Muddy Water!)
I don't like Level 1 dungeons, except Purity Forest because cutie Celebi is there.