1up.com for games. Rottentomatoes.com for movies.
Reading full movie reviews is dumb. You just end up spoiling the movie because the reviewer has to write an entire article about something that lasted less than 2 hours. You can't do that without giving away important plot points and ruining the movie for the reader. Games, being interactive, give the reviewer much more flexibility to talk about really important things that don't spoil the story. Visuals, sound, gameplay, connectivity, replayability, etc. Even still, game reviews sometimes contain spoilers, but they're much rarer and easier to skip. It makes sense to read a full review before buying a videogame and spending 10-70+ hours of your life on it. It doesn't make sense with movies. Rotten Tomatoes is where it's out. It ain't perfect, but it's by far the best thing out there.
As for videogames, the quality of the reviews on 1up.com are of a far higher quality than IGN.com. Actually, for videogames, zeropunctuation is where it's really at. That guy is ---smurfing--- awesome.