I can't vouch for its authenticity, but here's a supposedly real picture of Joker from the next Batman movie...
Regardless of whether this is real or not, this is probably the general direction they'll go with the character. I really never had more than passing interest in the first 2 Batman movies (and a passing hatred of the last two!), so this is the first real Batman movie I've loved.
Cillian Murphy, yeah, he was awesome, my favorite Batman villain out of all of the movies. If you want to see another great performance from him, rent 28 Days Later, though I should warn you that his weiner makes more than one appearance. Still, the movie is great and he's great in it.
I can't remember if Scarecrow died or if he was just put into a hospital? I would like to see him come back in the next movie, he wasn't really given enough to do in the first.
I've read that the studio is still trying to decide whether they should continue with the darker path or go lighter again in the next one, which is just ridiculous. Batman Begins had great word of mouth and eventually did great business (though, admittedly, it did stumble a bit when it first opened), but I think that's because they had trouble marketing it. I'm sure their natural thing would be to market it to little kids: it is a Batman movie, after all, and studios basically market to kids anyway (hence the fact that there have hardly been any R-rated studio horror films since The Ring did so well). However, I don't really think it is a movie that kids will like very much, and younger kids will certainly be scared at a lot of the imagery.
If it were my decision, I'd say go ahead and try to market it to adults, there are plenty of adults willing to admit they like Batman, and plenty more who like it whether they admit it or not. But, we'll see, I guess, that's a long way off.