Note that I did not say "
user-upgradable."

Certainly not like the Pro models. Nor would I suggest that even the mini be opened by most people. While it is possible and I've opened one several times, it is simply not a task to undertake without knowing what can happen and having at least the proper 'pry-bar' tool handy. Of course, adding RAM could not be simpler on the iMac or Pro. But that still would require the same case-opening procedure on the mini. But I always suggest buying RAM on your own.

Personally, I think the iMacs are usually the best product for the most people. The displays are gorgeous, the drives are quite adequate and external backup drives are cheaper than ever. FireWire 800 being more than sufficient for most people, also.
Lastly, don't forget about the refurb path! Usually around 11—15% less than new and they already have any failures repaired (which
usually happens in the first 90 days) and are still eligible for full AppleCare!
BTW, I don't think Apple will ever support eSATA until/unless they decide Thunderbolt is going to flop.

I agree with all of the above, and how could I ever disagree with Paddy?