Flat File Forums with CI

[eluser]dpgtfc[/eluser]
Hey guys, I am working on a general Forum for CI using Modular Extensions and have decided I would like to make it flat file with the option to switch over to MySQL. It would be php5 only (though I suppose it could easily be converted to use with php4 for MySQL) and I was wondering what people though would be best for the flat file system.

Since I plan on having this forum have most of the functionality phpBB incorporates, I was thinking either, XML, JSON or SQLite.

What do you think would be best?

[eluser]Jamie Rumbelow[/eluser]
I would use JSON, it's faster (and a damned sight cooler) than XML, but SQLite3 is equally as good. I suppose you wouldn't have to write a db driver for SQLite3.

FYI, I am actually writing a database system that uses JSON (kinda like CouchDB).

[eluser]Xeoncross[/eluser]
Use SQLite, if it is a forum worth running - then it needs a real DB. Plain Flat Files are only good for 10 users on a shout box.