I read an article a few weeks ago that said the R* team actually used Google street-view for some of their initial searching, just like us.
Then they went to the real life locations to get more photos.
I suppose we are just re-tracing their steps, but we don't have many clues to go on, we've just gotta keep searching.
There are tons of interesting buildings that weren't chosen for the game. They probably needed to get a good balance of interesting & "standard" looking buildings.
Retail plaza that is used twice in Sth LS & once in Morningwood.
It might be used somewhere else in the game, but I'm not 100% sure.
Real life. Nix Check Cashing Plaza, South Figueroa St & West Slauson Ave, Los Angeles.
In game 1. Zany-Z's Plaza, Innocence Blvd & Davis Ave, Sth Los Santos. (full version)
In game 2. Cart-L Market Plaza, Innocence Blvd & Carson Ave, Sth Los Santos. (shortened version)
In game 3. Binco & Ammu-Nation Plaza, Blvd Del Perro & N Rockford Dr, Morningwood. (shortened version)