For me the only really interesting "Bangle" design is...the e65.
I find it ugly, don't get me wrong. But it's really interesting, you feel the novelty of the ideas, the courage of the designer.

The 5er is less interesting, the front is very weak and smallish while the rear has nothing particularly attractive. The 3er is almost Japanese.

Bangle had to water down its views, make too much compromizes, and it killed its design and made it more and more unattractive and unspectacular, less "love or hate".

The new X5 is an old X5 with smoothened, more modern lines, but extraordinarily similar in spirit to the old one. Would it be slightly smaller, you wouldn't see it's the new one.
The 6er could have looked good, but the sad and smallish face ruins everything.
The Z4 has good proportions but is completely overdesigned.

The e92 is the only really beautiful modern BMW IMO. That is a design. No need to explain it, to convince yourself that with time you'll get used to it, or to detect weird lines and say yourself it's complex so it's good. Just look at the thing, and that's all. More emotional, more appealing than every other BMW. It is the only one that manages to get the spirit of older BMW without forgetting it has changed of century.

The X6 is interesting. Looks a bit heavy from certain angles, but overall it's quite beautiful. Like it a lot.

The design is more refined now, it has evolved and is more mature (it was high time).

However, the design is already changing direction with the CS. Superb concept car BTW. The new 7er does not look that promising but it's only a partly camoed car we saw so far.

So I could say the design was interesting at the first try, was watered down after it and lost its appeal, but begins to look good only now. And is about to evolve once again. I honestly think with time, everybody will agree these Bangle times were a failure and allowed Audi to catch up. Just like the Chrysler thing was a failure, and allowed Audi to catch up. For me the success of Audi is mostly due to the relative weakness of the two major competitors at this time (the design of BMW, and the reliability/finition at MB).

Just look as everybody begins to moke and ruin the e65 now that a new 7er is about to come... I've never like the e65, but would not moke it. It was ugly, but very inspiring for the competitors. A first try that, for me, BMW never continued, only watered down. BMW lacked the courage to go on with that design, but had no new idea, as a result the following cars were only Americanized, not very pretty cars. It's only much later that emotion came back to BMW.

Just my two cents...