As @Michael Verzijl says, the OBIEE SampleApp is a superb place to go for inspiration for (i.e. to rip-off ) what's possible with OBIEE visualisations.

In terms of "good", it depends. There's "fancy that looks good in a presentation for the Board/Client" good, and there's "communicates the data in a clear and comprehensible way" good. Ideally, you want both. Sometimes you have to choose.

This article is worth a read : http://www.rittmanmead.com/blog/2014/07/simple-ways-to-simplify-quick-fixes-to-enhance-obiee-visuals/ as is the work of Stephen Few - you may not agree with it all, but it sets out clearly the kinds of arguments and points to be thinking about when you're looking to build "good" reports and visualisations.