Thought I would add some additional information. I like to open the Find/Replace dialog in the newer "Regular Expressions + Find and Replace" mode. The command you require for this is:
Rename ADVANCED PRESET=regexpfindrep
although the following works the same
Rename PRESET=regexpfindrep
Note: The Ctrl+3 hotkey is assigned to the main toolbar heading button (labeled "Rename") and not the dropdown button immediately below (labeled "Rename Ctrl+3"). If you wish Ctrl+3 to default to "Regular Expressions + Find and Replace" mode you must edit the command in the former. Alternatively you could leave the main button alone and edit the dropdown button, assigning it a new hotkey, eg. Ctrl+5. Then Ctrl+3 would bring up "Standard Wildcard Rename", whilst Ctrl+5 would give "Regular Expressions + Find and Replace" mode. I did the latter for flexibility.
This is not in the documentation (as of today); I just made a guess at what the developer would call this preset if it existed, and it worked. Perhaps you could add it to the documentation Leo.