ROI in learning a foreign language is low, unless it is English. But if you must, I would say the next best thing to immersive instruction would be to watch spanish hulu as an aid to learning. You'd get real conversions at conversational speeds.
So after gwern pointed out that there is a transcript and I have read it I made a back of the envelope calculation.
Assumptions: According to Wikipedia people with a bachelor's degree or higher make $56078 per year, so about $27 per hour. Learning German increases yearly income by 4% and learning it takes about 750 class hours, according to the foreign service institute. Learning Spanish increases income by 1.4% and takes 600 class hours to learn. If we assume that one class hour costs 11.25$ per hour (by glancing at various prices posted on different sites...
You know the drill - If it's worth saying, but not worth its own post (even in Discussion), then it goes here.