Thanks for clarifying.
The point about keeping the memory in case of warranty problems is well made.
I have not owned a Mac since the Mac classic days, and am really tempted to enter back in with a Mini - I can see quite a lot of uses for it. I have a lot of money invested in Windows hardware and software so a mini for me is only ever going to be an incremental move. That is why the base model is so tempting, but it is a pain to buy and then have to immediately upgrade (or pay Apple £80 in the UK for another 2G).
To be honest I am having a lot of problems deciding which spec to get.
You start with the base (still expensive compared to PCs but at £525 in the UK attractively priced), then you say well I need more RAM ... and before long you are wondering if you should get the quad core server. And then by the time you are looking at the quad core you say well on £50 more and I can buy an iMac and so on!