My opinion - Ctl-M is great when matching pairs are not on the same page. I use it a lot. I think highlighting the matching pair is a great idea and nicer than hitting ctl-M a bunch of times for nested parenthesis and stuff within a few lines.
I've seen some text editors put a bold underline on matching pairs when the cursor is in front of one. It would also be nice if the "IF, ELSIF, ELSE, END IF" would all be highlighted together if a cursor is placed on one. Better yet draw temporary lines to the left connecting IF/END IF's together in addition to highlighting matching pairs. Sounds hard to do, but that would be so cool if it did.