I have just updated to Minecraft 1.7.4 and now all of a sudden there are barely any mobs spawning. I checked to make sure that I was in normal difficult and I saw 1 creeper but that is all. Also I tried different difficulties. Another thing - mobs seem to to spawn normally in the nether and all other mobs except aggressive mobs spawn like they should. Please if you know how to fix this, please help!
What I found out was that this is glitch like mentioned in comments the render around 6 is about were it happens the best thing to do is to downgrade or to wait for the next update.