Whatsapp is the way forward. I've been using it for well over a year now as my primary communication method. I hardly use my text allowance now as most of my friends, family and colleagues use this.
In some respect it's better than texting as it also shows you when the recipient received it (you know if they have ignored you ). If their phone is switched off, it will show as undelivered. Much better than a text message delivery report!
You can send images, recordings and an array of other media. Those of you who have controlling wives, DO NOT tell them about Whatsapp as it now has a feature where you can send the recipient your current precise location (on a map and as a coordinate). If you're having an affair, she'll soon find out!