yeah the pimsleur deal is pretty pricey, but as discussed its pretty easy to find 'heavily discounted', like most things.
I was tempted to try a few at once like rosetta, but the pimsleur system is based around a timed recall system (ie how regularly you need to be reminded of something til you remember it) and they strongly suggest not mixing it with other sources.
Pimsleur works for me because i learn when traveling to and from work, i might not have time to do as much study on a more visual system.
But i'd love the hear about rosetta, and ive heard the FSI system is good, if a little stiff.