Help me, Betty Crocker!

The first 2 days of the work week have been a blur - and I needed something to bring me back to earth.  I needed a bit of chocolate chip therapy.

So tonight I set out to make my stand-by chocolate chip cookie recipe.  This was the 2nd time I've made the cookies since moving into the new house (and we all know that adjusting to a new oven is an ordeal) - and the last time I made them, the cookies turned out perfect.  They were dense and thick - they did not spread out too much, but they were golden brown and delicious right out of the oven.  They looked similar to the cookies below...



I thought that maybe baking in a gas oven (instead of electric, like all of my previous attempts) had made my cookies turn out perfect-o.  I did everything the same tonight, but the cookies turned out to be flat and wide. (Like below)

I know that a cookie is a cookie and that those made by one recipe will taste the same.  But does anyone have any advice on how to get my cookies to turn out like the first batch?  And please, for goodness sakes, tell me what I'm doing wrong that they never turn out the same way twice in a row!