I was doing a global search in one of my projects when I noticed that ST2 was using a huge amount of memory. I narrowed down the culprit to a single 84 MB text file. When doing a multiple file search of "Open files and folders" with only that file open, ST2's memory usage shot up to almost 3 GB (all of my free memory). Then it stopped responding and I had to force quit it.
This only happens if I do a multiple file search, a regular single file search of the same file works fine. It's not specific to the particular file, I tried it with a couple of other big files and experienced the same behavior.
Running OS X 10.6.8 with a fresh copy of ST2 build 2210.