This is really quite an easy problem to solve. Run the upsell. If only a small percentage of users go for it, throw it away, since it's probably doing more harm than good.

I no longer use godaddy, partly because I got tired of wading through their ridiculous number of upsells. There's got to be a balance.

You're talking to a former salesman here — the art of the virtuous upsell is a delicate bit of work that takes time to practice. For humans. Very few ecommerce companies give a damn about doing the algorithmic legwork necessary to upsell "the right deal."

Even Amazon, the crem de la crem in ecommerce IT magic, doesn't often nail it for me. They get away with it, though, by being respectful to me. No interstitial horseshit, just a respectful suggestion that doesn't ever detract from my main activity — buying the things I am certain I want.

You can make money by surprising your users — Google made billions doing this with AdWords. It works for them by being good on a pretty solid basis and never being in the way when it isn't.