I myself tried Thunderbird. But I don't know how to make it work with Vidalia. and since Vidalia is my only option I used Google Chrome. Yes Google Chrome. Visit their webstore and find something that's name **Offline Gmail**. just do the search and install the app. (you should also allow it in your google accounts)
it's a simple app that retrieves your email while there's an internet connection, and saves it so you can retrieve your emails even if you found no internet connection. (very very good for very very slow connections like 3G) simple UI. but really useful.
and yes before i forget, make sure you have Google chrome 16 and later (mine is 17) for less bugs. (well Ive never seen a bug since I first used it, but just in case)