If we're interested in clothes or leather goods, are we better off buying in Rome or Florence?
Leather definitely in Florence. If you're there on a Saturday there's a huge multi-block market that sells primarily leather goods.
As far as just clothes, more options in Rome with major shopping areas on Via Corso, Via Condotti, Via Nazionale, and/or Cola di Rienzo.
There are numerous clothes and leather outlets in Rome. And many on-the-street markets. Or you can journey by car outside Florence to the Prada Outlet, Lo Spaccio!
Need info drop me a line, I've got some on my palm pilot.
Ciao!