I made A-List on WN yesterday, and I thought I would post an update here in case anybody is still reading this thread, or somebody in a similar situation is ever looking at it for advice:

I ended up using WN for nearly all of my commute in 2011, and I am very happy with the decision. Probably half of my flights were $59, and the other half were still relatively affordable. WN has had two big advantages over the competitors I considered:

1, No change fees. This has been huge. I buy months worth of tickets at a low fare before I know whether I will be able to cancel my trip for one week, or whether a conference, meeting, or dinner will require me to postpone my late flight until the following morning. Plus, if a fare sale drops the price of a ticket I have already bought, I can rebook the ticket for the lower fare. This has saved me several hundred dollars in a few months-- possibly more.

2, SJC. I can choose between flying out of SFO or SJC, and WN has much better flights for my schedule in and out of SJC. I don't drive to the airport, and accessing SJC by train is probably 15 minutes faster in the evening, and more like 30 minutes faster in the morning, when you can't take the BART directly from SFO to the Caltrain. The long walks and the airtrain at SFO take forever. SJC also has better food options (not great, but better than SFO).

I know people complain about a lot of stuff on WN, but for my weekly budget-conscious short-haul flights, they've been a hands-down winner.