One important thing to note with your setup is that the XMPP gateway for Google Talk doesn't support Hangouts group chats, so if you get invited to one you can't access it over XMPP, and you'll need to open it in your browser or using a Hangouts client.
You can however, create an XMPP-based group chat on Google Talk that Hangouts client's can't connect to, which is a bit odd, but a hangover (pun attempted!) from the old XMPP server days.
Also, accessing photos over the Google Talk XMPP server is pretty crappy having to open links to your browser rather than viewing them inline.
Skype has always been reluctant (slight euphemism there) to let third party software connect to its network.
Although this whole idea was kinda put on its head with the release of the SkypeKit library. Unfortunately its licence is specifically open-source incompatible so it can't be used in Pidgin (but it is used in Trillian) - so for now you're stuck with the other Skype plugin for Pidgin.
Remember: Silly is a state of Mind, Stupid is a way of Life. -- Dave Butler