These are the apps I have installed on my Macbook Pro for my texting, messaging and IM. Messages (default app from Mac OS X), Skype, Facetime, Adium (For MSN only), Tweetbot, Tweetdeck, Wedge (for App.net) and Viber.
And these are the chat services I use on my browser for other IM needs. Facebook chat and Google Talk.
These are the apps I have on my iPhone 5 that I use for texting, messaging and IM. Messages (default app on iOS), Skype, Facebook Messenger Chat, Whatsapp, Google+ Messenger, Tweetbot, Netbot (for App.net) and Viber
I would seriously pay someone a fortune for an app to consolidate all these services into a single app across iOS and Mac OS X.