How to choose a tool for mapping?

[Mark Oliva]

.I whish I could find modern and sci-fi buildings to add to my city maps, but it seems that I'll have to make them all from scratch, which would take a long time to finish enough buildings that would be feasible for use on sci-fi town/city maps.

You have my sympathy, but there's not much more that I can offer on that point.

If you want to build a modern or futuristic world, you will probably need Cosmographer, and probably SS3 (symbol set 3).

Symbol Set 3 won't do much for you on the futuristic side. It's modern in the sense of a little while before the present, mirroring the late 20th century but not yet into the 21st.