Pokemon cards were my introduction to the series as a whole, I got a handful from a friend back when I was 7 years old. As of last calculating, I had roughly 4000 cards altogether (including energy)!
I have two binders for bulk non-standard Pokemon, a binder for Trainer cards, a binder for standard Pokemon, and a binder for cards that are rare/special/have art I really like. I have 3 Elite Trainer Boxes filled with organized energy cards, one for my competitive TCG stuff (damage dice, deck boxes, coins), and a Trainer Toolkit box that holds extra card sleeves, dice and my Pokemon World Championship deck cards.
I don't have cards that are worth a whole bunch, and it was pretty hard to photograph things properly, but I have about 50 lvl.X/EX/MEGA/BREAK/GX/V/VMAX cards combined, from various generations. I don't have a favorite, but my first EX was a Kyurem that came with a tin!