I'm a big fan of display terrariums, for me it's the only way to go. So I'll throw in what I've learned so far.
Attractive, humidity-keeping subs are reptile bark and coconut husk. Both will do the job. My experience with reptile bark is that it looks very nice, but isn't so absorbent, so you need to mist more often. I also don't recommend you feed on it, or you risk impaction.
Coconut husk is a lot more absorbent, which also means its easier to spot clean. It is messier though, because it's so loose. I've been using it for months and I find it works very well. I water it heavily every few days, let it dry out again, and repeat.
The most attractive and effective hides, for me, are slabs of cork bark. Buy a few slabs and just leave them in there. They don't need to be supported on anything because they are easily light enough for the snake to crawl underneath and lift them up. This provides the kind of close-contact that BPs love. I have a half-log on the warm end of the terrarium, but you're right, they are definitely less desirable.
Decor- driftwood is great stuff. Get a nice sized branch or two and you will find that the snakes will climb on it at night. My BP gets very inquisitive when I add new driftwood, lots of activity and crawling around on it. It's fascinating to watch. I also recommend a rock or two, they add to the look and are useful in shedding.
On plants- my experience with live plants has been very negative. You need to watch your light conditions, you need to watch out for insects, and then the plants get trampled anyway. Fake plants with silk leaves work much, much better. They are durable, add to the ambiance, and they can provide a little more cover.
I would post photos but my camera is not working properly. If I can fix it I'll take some.