I agree. 9mm parabellum is SO much easier to find, and cheaper too. More powerful, more options in self defense loads, etc. If it's a choice between 9mm Makarov and 9mm Luger/parabellum, go with the latter.
This isn't to say that 9x18 is a poor choice. I carried one for years, but now in retrospect I like something a little more powerful (I carry a .45acp). 9mm Makarov is virtually identical to .380acp. I never had a problem finding Makarov ammo, but it's much easier to find 9x19 than 9x18.