Right now I'm using Sparrow, because of how well it works with gmail in a gmail-like fashion. However, I'm now forced to use Thunderbird because of a couple of extensions, and I'd like it to integrate better with gmail.
What I'm looking for is mostly a similar behavior for archive and that the folder tree is respected (sent messages go inside [gmail]/[sent mail], etc...) Also: similar conversation view.
Any ideas? What do you guys know of?