We're flying to Denver over Christmas/New Year, so I'm waiting for prices to come out Monday.
DH and I both got a SW credit card the summer of 2011. The promo then was for 50,000 with your first purchase (no dollar limit). I bought a Skinny Cow candy bar and he used his to pay for prescriptions at the pharmacy. This will be our third trip to Colorado and we are still using our points. I'm not sure if they will ever go back to the first purchase promo with no dollar limit for the points, but it would be great if they did!
What I've learned booking with them is to ALWAYS book my flights separately. That way if the price/points drop one way and not the other, I can easily switch to the lower price. Also, the really early flights or really late flights seem to be the cheapest (at least for us). We've done the first flight of the day and the last flight of the day for the cheaper rates.
Also, keep checking even after you book. I was able to go from paying 10,000 points to 6500 points (one way) just by checking daily.
Good Luck Monday!