Google Talk is plain vanilla XMPP (except the audio/video extensions), and any XMPP server can chat to any Google Talk user. The Google Talk client itself is shit and hasn't been updated in years, you won't be missing out on anything there.

I use Mail.app w/ GMail over IMAP and have no problems. I could switch to any other provider of course, but see no reason to do so as accessing GMail over IMAP doesn't have any of this social crap associated with it. Unfortunately, on Windows I'm forced to use gmail.com as no desktop client comes even close to Mail.app's fully integrated and optimized IMAP support. Outlook's IMAP support is STILL blocking/synchronous for most operations, hanging the entire software while it syncs headers or sends items to be erased. Thunderbird is as clunky as ever.

Google is the only one left, then. I used DDG for a while, but I think they need to step up their game with regards to simplifying the UI (i.e. remove the attempts at finding the info you're looking for for you or at least provide an option to disable this) and speed up both page serves and queries, w/ geodistributed caching, etc.

Or you could just use Google SSL, but disable all cookies for that domain.