I'm not a fan of text messages, as a rule. Communication-wise, I'd much rather have a conversation.
That said, they are very useful for the "I'm running late", "did you pick up the milk" sort of things. And I agree that they're useful for times when you need to communicate privately.
Txtspeak really annoys me. I always try and write out full words, use capitalization (unless I'm in a big hurry) and punctuation. It's one thing if you're typing via a number-pad or something, but most phones have some sort of keyboard and I don't think it's too hard to type a few extra characters for clarity (and to avoid looking dim).
I did commit the cardinal sin of ending a relationship via text message...however, it was the end to a conversation that we'd been having for over a week, so it wasn't just an out of the blue "things aren't working", and I used the text message for privacy. I still feel kind of guilty, though.
