Embedded database recommendations?

[Drew Van Zandt]

Hey guys...
   I'm shopping for an open-source database for embedded use, biggest
expected install around 230 million records stored per month.  From
google research I think I've narrowed it down to SQLite or Firebird
(postgre and mysql aren't embeddable enough, etc.) but I could really
use some group discussion to help me make up my mind and make sure I
haven't missed something better than those two.  Must be able to run
compiled in to another app or as DLL, as SQLite and Firebird can...
anyone have experiences pro or con?

--DTVZ