I do not generally max things out, even though I could do it because I leveled up a few days ago.
I will max out Raikou (96%), Blissey 87% P/DG, Mewtwo (which I don't have yet), Dragonite 89% DT/O, Moltres FS/O 93%, Rhydon MS/EQ 93% and Flareon FS/Ft 100%.
For most of them it's because they're useful, and Fire Mons are probably just added in because I like them.
I should actually add my Conf/SoB 93% Exegguttor because it kills and a Bodyslam 84% Snorlax because it's my favourite pokémon.