FYI on modern LaTeX engines like LuaLaTeX (and also XeLaTeX) Latin Modern actually is the default.
But Latin Modern and the default Type 1 version of Computer Modern have exactly the same thickness, so if Computer Modern looks thinner for you then it must be some weird screen effect. (The hinting is a bit different, but I wouldn't have expected that to have a significant effect on current systems where hinting is often ignored anyway.)
AFAIK, Wikipedia's info on the Latin Modern regressions from Blue Sky is accurate. Neither version is the original CM font or has had as much fine-tuning put into it, but (EDIT) the Blue Sky version was at least worked on by paid professionals.
But Latin Modern and the default Type 1 version of Computer Modern have exactly the same thickness, so if Computer Modern looks thinner for you then it must be some weird screen effect. (The hinting is a bit different, but I wouldn't have expected that to have a significant effect on current systems where hinting is often ignored anyway.)