Personally, I loved Pokemon Black and White. The plot was thicker than any previous installment, the human characters actually had deeper backgrounds than any I've ever known, and the Pokemon themselves! I can't disagree that they were different, it's just that they had a certain charm about them that allowed me to delve deeper into the games. However, I can't say that Pokemon Black and White were my favorite games. No, I'd say that HGSS were my favorites.
The things I loved the most about B/W was, as I said before, the deeper plot. Even the gym leaders got involved, when they usually just seem to rot away in their gyms. N had to have been the coolest antagonist ever. He was so engaged throughout the storyline, and he actually seemed to fit. It was as if the developers created the game based around you and N simultaneously, not like previous games where they seemed to stick your rival in wherever there seemed to be room for a Pokemon battle that meant nothing more than a show of power.
However, I can't say Black and White was flawless. A few of the issues I have with the game may seem trivial to some of you, but to me it sort of stole the usual "perfection" that Pokemon games usually bring. The biggest flaw that I noticed, was that you couldn't challenge people to 6v6 online, you were limited to 3v3. This in my opinion is the core reason why my attention span with this game deteriorated rapidly.
I want to play this game, which is really sad because as soon as I pop it into my DS and turn it on, my desire to play disappears and I have to put it away or else I'll stare at it longingly.