Alright BW, I'mma letchu finish, but...HGSS HAD THE BEST BAG OF ALL TIME!!! BW was a pain to scroll through. :/ RSE takes second for me, then GSC, BW, RBY, DPPT. DPPT was terrible. Not only was it infinite, but if you have an older file where you're well stocked on items, you have to scroll through infinity to get to the bottom of that bag. With GSC and RSE, you don't have unlimited space, but at least you have your pockets and with that limited space, you don't get that problem of taking forever to get to the bottom of the bag. HGSS had it perfect. Scroll from side to side, with pages in the pocket, and nice sized item icons so you can clearly see what you're looking at.
Edit: I agree with BW having too few pockets. What happened to the Pokeball pocket? Now that was annoying. I'd be preparing to go catch a legendary and I'd need to check my stock, but you can't do that with all the other clutter in the way. Cause all the Pokeballs, X items, repels, and hold items go in the same pouch. Why? Just go act like you're buying Pokeballs and that's an easier way to check your stock. But even still, that could be out of the way. Should just be able to look in the bag and see that you have 17 Ultra Balls or whatever.
Vietnamese Crystal had the best way to put items in your bag, though.