I just have to say, I think that Black/White may just be my favourite games, in what is undoubtedly my favourite video-game series of all time. I'm constantly amazed at the depth and the variety of things to do in mainline Pokemon games. I've put in around 240 hours on my primary Black version (I bought both, blitzed through White in 20 hours, figured I'd get both for future events and version exclusives), and I still haven't burnt out yet. There's ALWAYS something to do, and the games are designed in a way that makes it easy to jump back in if you do happen to stop playing for a while.
To illustrate my point, let me summarise what I've achieved in my 240 hours of playtime. I've finished the main story (obviously), gone through most/all of the post-game content, completed my National Pokedex (which was not nearly as time consuming as I'd anticipated it would be, thankfully). I've levelled up a bunch of Pokemon (particularly legendaries) to level 100, because I find reaching that milestone to be satisfying. It sort of signals a symbolic endpoint for me and that Pokemon: I've helped it reach it's full potential, and now I'll never need to bring it out of it's box again. For this reason alone, the new level-scaling system has been a god-send: this was a much more painful experience in Gen IV.
Lately, I've been attempting to breed for shinies using the Masuda method. I've gotten a Charmander (now Charizard) and a Pineco so far, as they're 2 of my favourite Pokemon. My plan is to eventually breed a full party of Gen III Pokemon to trade over for the Ruby/Sapphire remakes (I'm really hoping this is what the May announcement will be, as I never got to experience Gen III, but at the same time I think I may need more time to breed my whole party of shinies!) At the moment I'm thinking all three Hoenn starters, Beldum, Bagon and a couple of HM slaves (figure I'll need at least one in my party at all times).
And just in the past week, I've started to build my ideal 'capturing party' (to transfer to any future games, for the express purpose of catching legendaries). So far I've got 4 Pokemon designed specifically for capturing. I've got 2 Smeargles: 1 designed to be able to fend for himself (he knows Mean Look/Heal Block/Spore/False Swipe, and ability is Technician), and 1 designed to back up another catcher (this guy knows Ingrain/Aqua Ring/Odor Sleuth/Baton Pass, ability is Own Tempo). He pairs up with my Breloom (False Swipe/Seed Bomb/Spore/Stun Spore, ability Poison Heal), passing on HP regeneration and the ability to hit Ghosts if required with Baton Pass. That covers most scenarios encountered when capturing, but I decided there's a lack of firepower when it comes to depleting a Pokemon's HP. Rather than relying solely on multiple False Swipes to weaken foes, I've bred a Sturdy Aron to learn Endeavour. It's at Level 1, and I don't plan on ever training it, otherwise it will lose it's effectiveness: I'll lead with him, he'll take the first hit, hold on with Sturdy and bring the foe down to 1HP with Endeavour: it's perfect, as long as he doesn't flinch, or get hit with a multiple-hit move.
This is exactly what I'm talking about: the fact I'm able to write a whole paragraph about building a capture party (admittedly a pretty mundane topic) reveals just how insanely deep these games can be. There's a staggering level of detail to be found, but it's not required to play or enjoy these games, as the barrier for entry to the series is incredibly low. And I don't even dabble into competitive battling or EV/IV stuff (just not interested in it): it seems absurd to me that there's a whole meta-game I'm essentially ignoring when there's simply so much to do in the product already.
So, tl;dr version - Pokemon is great, Black/White are the best in the series in my opinion, and I have way too much spare time on my hands.