I was reading the comments on this topic since I want a real good Desktop client to use with Google Apps. Yes, that's right, the Gmail UI is terrible for people who user the mail for work purposes. It can be "nice" if you use it for your personal email but for me it's a mess.
I've used Opera Mail client when my company used it's own mail server and it was PERFECT, slick, fast and powerful. EXACTLY wat I've been looking for. Of course I would've liked some addons but it was good as it is.
Migrating to Google emphesized the limits of this software: the first thing is the lack of Identities tha I must use in Google - this is a huge problem. Second the conversation view of Opera is not as powerful as for instance Postbox mail, and of course the fact that it SI a DEAD software dowsn'y help much....
Well, I discovered a new project called Vivaldi (from the former CEO of Opera) anc they think of making a browser and a mail client bundled togather (as was Opera in the first place).
So....as soon as they're ready I'll test the product hoping for something as good as Opera Mail.
Elio