I do not like to chat, specially because it takes to much time to have a small conversation, If I have something really urgent to tell someone I call him, if it is not that important, I write an email, that way the other person may respond whenever he has time.
But, for my family I have been testing some messenger clients, messenger for the smart phones, I have tried whatsapp, and Google Talk. After some testing I have decided that for me Google Talk have some features I prefer over Whatsapp.
What I like the most is that you are not stuck at your cell phone, you can start a chat in you phone while on the go, and then continue it on you computer when at home, whatsapp works only on your cell phone, and even if you ar near a computer, and you may want to use a comfortable keyboard you are constrained to your phone tiny keyboard. One more thing I like, is that all your chat history is stored in a centralized place in your gmail inbox.
One small pitfall is that there is no native client for the iphone, but you can use IM+ for it. Once google is able to release an official app for the iPhone it will have the same features like Facebook chat.
If you want to share files, you will have to use gmail, as you can not share files using the phone clients.
One good thing is that considering all of these options use push technology, you can have all of them installed and active on your phone and do not observe big battery issues