For all the talk about SW being a "discout" carrier, I've found that I can usually do much better with Continental or even Delta (with internet fares). SW only seems to be cheap when I'm going one way.
Last year I flew about 14 round trips from MCO-IAH/HOU and MCO-AUS (parents and finacee living in houston/austin), and only once was SW the cheapest. CO and SW are strong in all 3 cities, but CO consistently seemed to beat SW by $50 or so on fare. And they give you a sandwich and sometimes movies/video games!
Now I'm married so I'm not flying to Austin nearly as much - I can spend that money on my flying!