The TV trailers make it seem like a re-make of Omega Man with Charlton Heston.
Omega Man was a great film..
I am Legend seems to be a remake (what isn't nowadays) of a film back in the 50's where Sidney Poitier plays a subway inspector and when he contacts his boss, gets nothing in answer, and emerging from the subway finds a destitute NYC w/ noone. He later finds a white woman and just when they seem to realize that they are new Adam and Eve, a white man appears. Wel you know this was the late 50's-early 60's, so you have an inkling what happens.
In the end they make peace as they go out in the world seeking other survivors, (who are hinted at during various times in the movie) I know it didn't have the SFX that the modern movie does, but nonetheless a good movie anyway.