Hm... I don't really know about how I'd rate them, but I really like Black and White. So, I guess I'll just put down a few things and have my say about them--although, a lot of it has been said already.
-Storyline: I absolutely loved the story. Like, no joke. Usually, I just play through the games and not really pay attention to what's going on because it was extremely predictable. Bad guy does this, you stop him, find a hint about the next area, repeat. Not to say that Black and White wasn't predictable. It was just more... interesting this time around that I never noticed. I actually wanted to see what would happen and took my time doing so.
-Character Development: This is another thing in the Pokemon games that I usually find lacking. Characters, save for a few, remained static throughout the entire game regardless of their roles (exceptions being, say, Silver/Rival from the Gold and Silver series, Wally to an extent in the Ruby and Sapphire series... there's probably more that I forgot). But the fact that your rivals went through and matured as the journey progressed made me smile. N... well, you'll see.
-Graphics: I don't know about you, but I liked just about all of the graphic and animation work done in this game. Even the battle animations. Sure, it does seem a bit... excessive at times, but it made the battles feel a hell of a lot faster to me--plus, I like seeing my Pokemon actually move. I played my Diamond game recently to check over any PC Pokemon and battled for the heck of it... and I felt like it went on forever. I turned off the battle animations and it still took a long time just watching the HP go down on a wild Pokemon battle. Or maybe that's just me. Also, Castelia City and the bridge. THE BRIDGE, DEAR LORD. First time walking down it, my expression was O_O the whole time.
-Main Character Design: I liked them both. Yes, both. Even the female. Why? Okay, yeah, she wears short shorts and a tank top that many people find revealing, but I find that it makes her look really... natural. Casual? Either way, I like her more than most of the other female protagonists. I especially like the flaps on her shorts. They remind me of Reshiram's wings, oddly enough, so I thought it fit.
-Music: Black and White have a really good soundtrack in my opinion. Say what you want, but there are some areas that I just enjoy visiting from time to time just to listen to the music (Dragonspiral/Celestial Tower, for instance).
-Gyms: And their leaders. I liked the designs of a lot of them. I guess I can blame the computer but the battles with a few of them were just... AUGH-worthy. Or maybe I have bad luck. But anyways, I also found them pretty cool because they actually had another role other than to sit in their Gym, fight, and look pretty. Mainly talking about them coming to the rescue when you're about to be attacked by the Sages. Branching off, Shauntal and Grimsley of the Elite Four really got to me. Shauntal's outfit made me WTF all through her battle and Grimsley reminded me of Ryoji Mochizuki from Persona 3 design-wise.
-N: THIS GUY. Love 'im, yet I hate 'im. He's complete creeper status when you first meet, turned total hypocrite due to the fact that nobody thought to animate him sending his friends out to battle out of a ball, and yet he grew on me. I think it was his backstory. Poor guy, disillusioned by an ass of a father.
-Pokemon: Some of them creep me out to this day (and probably forevermore), such as Conkeldurr and his pre-evolutions (those veins sticking out... no amount of gameplay will ever stop my eye from twitching upon first sight in a battle) and Alomomolamolalamola. All the other ones have grown on me. Even the genies (I just think they're ugly).
I actually had a lot more to say, but I figured this was enough considering...