The crash reports looked like this:

Process:         Safari [700]
Path:            /Applications/Safari.app/Contents/MacOS/Safari
Identifier:      com.apple.Safari
Version:         3.2.3 (5525.28.3)
Build Info:      WebBrowser-55252803~5
Code Type:       X86 (Native)
Parent Process:  launchd [205]

Interval Since Last Report:          311 sec
Crashes Since Last Report:           1
Per-App Interval Since Last Report:  284 sec
Per-App Crashes Since Last Report:   1

Date/Time:       2009-05-26 09:04:32.111 -0500
OS Version:      Mac OS X 10.5.7 (9J61)
Report Version:  6
Anonymous UUID:  92C09E73-C6B0-4A8B-AA5F-46F13FF83479

Exception Type:  EXC_BAD_ACCESS (SIGBUS)
Exception Codes: KERN_PROTECTION_FAILURE at 0x0000000000000000
Crashed Thread:  4

I tried everything I could find, including trashing my Safari .plist file, and multiple runs at repairing permissions with the Disk Utility.

I eventually noticed that there was an alert message on the Safari preferences pane below the [ ] Warn when visiting a fraudulent website option option, indicating a problem pulling updated data from Google. Unchecking this option immediately resolved the Safari crashes.

Additional digging after the fact turned up this thread on Apple’s forums. I was able to confirm that this was also my problem. I was able to cause Safari to crash again by re-enabling the fraudulent website option. However, once I deleted the SafeBrowsing.db file (mine was in /private/var/folders/Gh/Ghnj4FQ2EjeLtxPyNkIUVU+++TM/-Caches-/com.apple.Safari/), Safari would run without any problems.

So, if Safari starts crashing with EXC_BAD_ACCESS errors, your SafeBrowsing.db file may have gotten corrupted. Fortunately, the fix is just to delete the existing one – Safari will create a new one the next time it’s opened (though it’s always prudent to create a backup first, just in case).

Hope this saves someone else from tearing their hair out.