Yet another wiki question. I would like to migrate away from using TiddlyWiki as a personal wiki to one capable of handling a lot more data, but I need one specific function. Here is an example of what I need. What I like about this is that the answer is obscured until I click on the question. I also appreciate the ability to nest a question inside another answer in case the next question would contain information that would allow you to answer the first question (ie. no hint for answering the first question with the second question).

I take a lot of notes in the form of questions while I'm reading. When I review I go back through these notes and answer the questions in my head. If you look at the example above that's exactly how I do it on TiddlyWiki. But, of course, TiddlyWiki has a problem with large file sizes. I have multiple large (ie. slow performance) TiddlyWiki files that, unfortunately, can't interface with one another being in separate files.

My primary note-taking computer is my Asus EEE running Ubuntu. I am open to running it on LAMP or whatever. It does not need to multi-user (but that would be alright). I'm pretty familiar with the existence of most of the wiki software out there, but I haven't had any experience using most of it. I'm looking at Dokuwiki maybe, but i haven't found if I can replicate this behavior in it.
Bonus points for:
- ability to print entries
- ability to export to pdf
- tagging or some other metainformation sorting/hierarchy
- ability to password protect

Superbonus points for being able to import TiddlyWiki data/syntax.

If you have any other suggestions or alternate methods that would still allow me to review my notes in this manner I'd really appreciate hearing those also.