I was looking at the Firebird database recently. Free Software, very feature complete, and one neat feature was that it could run either client/server (like PostgreSQL) or as a standalone .so (like Sqlite). I was starting to look into using it.
Then I discovered it only supports i386 on Linux, and no progress has been made in 3 years on that.
So I will not be trying Firebird.
I thought we had all learned by now that portable code is a good thing. Guess not.
I will be sticking with PostgreSQL as my preferred RDBMS for awhile.