I would prefer Regular expressions to stick (since I use them almost always, in fact); and in the rare case when the search string has come from another program, to switch it off manually.
I won't make it sticky, but I'll add to the to-do that it should only clear when the string has changed from the last session. Expect it in 1.1b1 (which I do think I can promise will be before the new year) or 1.1b2.
When TextMate is running, I still can use Find in another program, such as Mail or Safari. In which case Regular Expression remains selected, but the string is not what was entered. I believe that the right behavior is to keep the setting for Regular Expressions. Alternatively, a consistent approach would be to drop it every time the clipbroad gets a new value not from the manual input with RE set.
So, the current behavior of TextMate is almost what I want (and does not cope well with the idea that literal find should switch RE off) except for one case -- when I restart TextMate. Fixing it to never keep RE or to always keep RE makes it consistent, and the former makes it less convenient for me.
What about Command-Option-F /Command-Option-G for regular expression search/replace; not interacting with Find clipboard, and just Option-F/Option-G for literal search/replace?
David Tolpin