My spelling sucks, but I know when to use which version of whatever homonym it is. I have an excuse (ESL... though my spelling in every language blows pretty hard - that's what happens when you're taught 3 at a time growing up ).
My biggest peeve is how it looks/feels etc. It's especially annoying because people who will correct others will miss that one or let it go. Don't even get me started on Let Forever Be; that song should have been sent back for vocal retake because it ruined grammar for at least 2 generations through bloody-minded repetition. A&R fail.
As for text speak, I don't mind that at all; it has it's place and can be used as a (for lack of a better term) poetic device. That said when you can't break out of it, use it all the time, and let it affect your ability to use proper language, then it's time to cut it out.