considering move to mac, convince me

[Copas <enter@email.here>]

I'm having trouble finding concise and comprehensive 
information on imacs, even at the store.  Sales persons 
don't get paid very much I guess, and don't even seem to 
understand simple questions.

Do the current on the shelf imacs have intel processors?

Will I be able to hookup existing Windows disks from an old 
Windows pc and transfer files off those that I want to 
keep?  If so, by what method?

Do imacs come with both an internal disk and an external 
disk stock?  I use pc's with several.

I can hardly believe 500MB of RAM could be sufficient for 
much these days, anyone know of where these are sold with 
standard RAM double that?

How much would I have to pay for partitioning software for 
an imac?  And backup software?

I have invested a lot of money on Windows PC's over the 
years, and expect I would have to invest much more were I 
to do the same things with an imac.  Are software prices 
for these still out of this world?

Thanks y'all.