@Thomas,
I've seen the my own post new issue only once, I'm not sure what causes it (we may actually need to slow the program down to fix it, I wonder if the thread is being marked read at the very same timestamp of the post sometimes) but it's very rare.
As for including ignore into the read tracking I am not sure if this is desirable. They may be ignored but the topic is still new, and others may want the new to be what it says on the tin. Also, what if the last post was a user ignored but the previous ones (also new) weren't? That becomes a very expensive calculation, no longer allowing us to use our db indexes and well, put it this way: it's an unlikely feature because it's very non-trivial and has high potential for confusion.