It is a bit difficult to predict the price of the iPad 2 because we do not know the latest technology that will be added in the device or the features it may have. I would say it would be around $499 to $599.
I can see
1st gen 16gb 499
2nd gen 32gb 599
2nd gen 64gb 699
Like they did for the iPods
Give it a year or so for flash storage to go down a bit more
You seem to be ignoring the fact that using 3G is still an option, not a requirement. Even if people don't have a need for 3G, if there was only one version that was sold and it came with 3G, it's not like people would refuse to buy it just because it includes it. The use of 3G is an option, there is no contract, and no default fees. There is no disadvantage at all to having the 3G option.
Also the assumption that a model without 3G is that much cheaper is wrong. The cost of manufacturing 3G modem is nothing. From what I understand most of the cost was in fees from AT&T and FCC taxes, not the additional manufacturing cost. Apple could easily work out a deal with AT&T where that wouldn't be a problem, especially if Verizon is offering a similar deal.
There is no reason why Apple can't get rid of the Wi-Fi only model. But they might choose to keep it separate for some particular reason that isn't about the cost of manufacturing the 3G parts.
As for the Bestbuy thing, I really hope you aren't taking that stuff to mean anything. It's completely unsubstantial and even has two models listed as $599 which makes no sense at all. Try not to read anything into it, because Apple still hasn't announced anything yet. Last year when a few iPad SKUs appeared in Bestbuy's database, it was actually after Apple had announced the iPad, but had not announced an official release date. This recent event would have been complete speculation on Bestbuy's part, because they have no advance knowledge of pricing or specs. They might have some advance knowledge of the number of different SKUs though (though just about anyone can guess that one).
Again, I say that Apple has plenty of reasons to drop the Wi-Fi only model and make 3G be default, with the base price of $499.