Reykjavik is a nice enough town, but my personal thought is that if you're there for the landscape then why go to the city. We spent a couple nights there and that was enough, I think we'd bypass altogether next time.

Only 16 identified? You must be skipping some to spare your wife
Both falls you mention were nice while we were there. Almost constant rainbows at Skogafoss with the very high volume of water and mist. I'd be interested to see what they are like in winter with all the ice. Very easy access for both; right alongside the ring road. How far south/east do you plan to go? We found Vik to be a nice town and a good base for southern Iceland.