LogDiff

LogDiff helps you find out what went wrong in a ProcMon trace. It does the following:

takes two related traces from ProcMon (the Windows Internals API monitor)
splits them into separate threads
matches the threads from one trace to the other, based on similarity (basically identifies which thread is which)
displays all the threads and their details in a sortable table
edits out all the numbers, timestamps, pointers, etc that shouldn't matter when comparing diffs
shows you a visual diff of any pair of threads, so you can see where the differences actually are

It uses KDiff3, GNU diff and grep, and Qt 4 (the Windows binary includes everything required to run). Tested on Windows, should compile on Unix.