ferretgirl said it best! Personally, I started off at 225lbs (March 2011) and this morning I weighed in at 195lbs.
I aimed for 10lbs a month and ended up successfully losing and maintaining about 5lbs - give or take a good/bad month. Do I wish the pounds peeled off faster? Yes! And, I'm sure if I worked HARDER (i.e. worked out every day, ate healthier, etc) it would..
Either way, minimum goal & ultimate goal are the way to go