I really like the Clash's first album the best. My very favorite Clash songs are right there---Janie Jones, White Man in Hammersmith Palais, London's burning, What's my name and Police and Thieves. As an LP London Calling diversified their music in a lot of different directions but the second LP IMO is not nearly as good as the first one there. It's a big improvement over their second LP Give 'em enough rope which was marred by too much production but also apart from Stay Free doesn't have any outstanding songs IMO which brings me back to the first album again in that to me there is a vibrancy, vitality and edge that comes out of it's rawness.
By the way some of the founding members of Stone Roses when they were teenagers use to follow the Clash all over England from gig to gig and were well known by the band and sometimes hung out with them.