For me I think it's clothes size (48 pants to 40- 4X shirts to 2X and XL) and being able to do things I couldn't do. This week I hiked Old Rag Mountain in Virginia (10+ mile round trip with a rock/boulder scramble). It was tough, tough, tough, but I did it. I KNOW 10 weeks ago I couldn't have made it.
10 weeks ago a 1/2 mile run nearly killed me. Now I'm doing 2 miles and I'm sure I can do more.
I went to Kings Dominion amusement park with my kids yesterday. I wore my swim trunks with nowhere near the the self-consciousness I would have 10 weeks ago. I got on one ride and a sign said, "Weight Limit 270 lbs." A few weeks ago that would've been me they were keeping off the ride.
So be able to wear and do things I couldn't not too long ago means I am hyper inspired right now.
There are certain clothes I want to wear (comfortably) that have been sitting in my closet new and too small for years and there is a 5K I want to run in under 38 minutes coming up. I'm trying to make those things more my goals that the pounds on the scale (though I've got those goals, too--looking for under 245 right now).