Multiple SKUs at launch is kind of a paradox. Everyone complained about $599, but no one wanted to buy the gimped 20GB SKU.
To me, it makes sense to produce only 1 SKU at launch. Release the cheaper SKU down the road once the hardcore early adopters are satiated.
The problem with Sony was that they focused on the $599.99 but added in the cheaper version as, "hey, BTW, you can get the cheaper version!"
SOny should take a cue from Google and Apple and focus on the cheaper SKU as the "main SKU," and the more expensive option as, "BTW, you can get a premium model too!"
Ideally though, yes, I'd like one affordable SKU, and the burn of what happened with $599.99 may still come back to haunt them, even if they focus on the cheaper SKU as the main SKU.