I just want to make sure... Arcane Ward will also counter your own spells, right? Nullify, for example, specifies the opponent's spells, but Arcane Ward doesn't.
This makes it more likely to be used on an object that you won't want to enchant any more or want to use your own incantations on. Some such likely uses would be on enchantments (Astral Anchor, curses, etc.) and I guess one of your opponent's creatures that you don't want buffed / teleported / etc.
I would presume that it would not go on one of your own creatures, unless you know for certain that you would not ever want to buff it, heal it, etc.
Are there any other considerations on the use of this spell?