Edited on 2010-12-19 to bump sqlite version.
It would be nice to have updated zlib and sqlite3 versions in the next release.
zlib 1.2.5 has been out for ~8 months, so it seems a safe upgrade to gain speed and bugfixes since 1.2.3.
sqlite 3.7.4 would provide FTS4 and WAL (as an option) for faster performance & more concurrency.
If upgrading to sqlite 3.7.x is a pain, then 18.104.22.168 would might be an alternative:
sqlite 22.214.171.124 fixes
* incremental_vacuum bug fix (255f1eefa373153942c67b18b)
* R-tree segfault bug fix (7f2f71cc9e3c39093f09231f44)