I started in July 2004 weighing about 200 lbs (I had stopped weighing myself and have no idea of my true start weight, I know it was more than 195 lbs).
I had various events that fall that make it easy for me to tie my weight loss to (I also bought new jeans at these increments, makes it easy to remember the size I was):
July 2004 - ~200 lbs - 37 inch waist, tight size 18
Sept - 165 lbs - size 16
Christmas - 150 lbs - size 14
March 2005 - 140 lbs - size 10
July 2005 - 138 lbs
November 2005 - 135 lbs
February 2006 - 127 lbs - 27 inch waist, size 6 (sometimes 8)
this morning - 128 lbs
I lost the first ~50 lbs very quickly, within 7 months. It took me almost another 9 months to lose the last ~15 lbs. I actually thought I was finished in March 2005 - I started maintaining
I was very surprised when I lost more weight!
Although it's easy advice to give and hard advice to take, I would recommend not worrying about how long it takes to lose the weight. When I first started, my only weight loss goal was to "lose some weight by Christmas" - I was going to visit my mom and I knew I wanted to lose some weight. I didn't put any pressure on myself to lose a certain number of lbs in a certain period of time! I had lots of goals that were related to improved health (and not specifically weight loss) that helped me stay motivated when the scale wasn't cooperative.