The 20100527 beta is out now, with changes centered around automatic indentation.
Firstly, the basic automatic indent system has been reworked: rather than using hard coded rules, it now uses TextMate preferences (decreaseIndentPattern and increaseIndentPattern in tmPreferences files) to determine when to increase and decrease the indentation level. The implementation goes something like this: when pressing enter, the desired amount of whitespace is inserted on the following line. This whitespace is marked with a magic tag, and it will be reevaluated as the line is edited. If the whitespace itself edited, or you start to edit another line, the magic tag will be removed, and the indentation on the line will be baked in.
The tag added to the whitespace is used for another purpose too: if you start editing another line without adding anything after the whitespace, the whitespace will be removed. This reduces the amount of unwanted trailing whitespace in files.
Another significant change is to the way paste works: when pasting in a block of lines, their indentation will be adjusted to match that of the cursor. You can paste with ctrl+shift+v to avoid this. This is a somewhat experimental change, and the behaviour may be reverted if it turns out to be annoying.