The ability to edit your own post is useful for the odd typo or inaccuracy but it can be abused and change the whole feel of the thread and make for difficult reading.
some sites give you a few minutes to edit your posts - not really enough to cause havoc by posting abuse then removing it - and then they're set in stone. I'm not really bothered, though, if I've said something wildly wrong I just add another post to correct it.
I would like to be able to click on the last poster's name on Latest posts to go straight to the end of the thread- like you can under My Profile and the topics. Not much else- might try to slow down some of the other Q&Pers to have a vague chance occasionally :-)
I like the idea of a few minutes to edit a post. I don't like to see my typos (I'd like to see the Preview button back) although in the great scheme of things, I don't suppose it matters.