Remakes are often bad because they're phoned in too ,to capitalize on the success of the orginal.

I'm sure if as much effort was put into a remake as an original then the remake would be great.

There are some examples of remakes that are great. Frequently, these become the "classics" and people forget about the original. A canonical example is John Carpenter's "The Thing" in 1982, which was a remake of a somewhat crappy 50s movie and is now a sci-fi horror classic. Another good example is "Invasion of the Body Snatchers" from 1978, starring Donald Sutherland. It was a remake of a 1950s movie too, though in that case the 50s movie was actually pretty good, but the 1978 one was scarier.

I can't think of any good remakes from after the year 2000.

Does the Coen Brothers 2010 version of True Grit count? I think it was better than the 1969 John Wayne version, but maybe it doesn't count as a "remake" because both were based on Charles Portis' novel.

I haven't seen either, but I do think it counts as a remake when they're based on the same novel.

Not a movie, but Battlestar Galactica was a great remake.

It was fantastic for about 2.5 seasons, and then jumped the shark. It really, really showed the importance of not just letting the writers make shit up with each new season, similar to LOST.