Switching to Ubuntu and thus not having textMate, one feature I really missed was the directory browsing. After you've installed the Python based App Engine launcher on Ubuntu or other linux, you need to make gEdit more powerful.
1. Download and extract the browser plugin for gEdit
2. Extract it. If you've downloaded into your download folder then you need to copy to /usr/share/gedit/plugins
- sudo cp -r ~/Downloads/gedit_classbrowser-0.2.1/ /usr/share/gedit/plugins/
3. In gEdit go to Edit -> Preferences -> Plugins and check the box for "File Browser Panel"
To make gedit even more like TextMate: blog.sudobits.com/2011/04/02/textmate-for-ubuntu-linux/