Well what's your RAM and operating system? Also, there is a link below that sort of explains the recommended settings and other things (Its not an official thread). Hope it helps!
http://www.minecraftforum.net/viewtopic.php?f=35&t=29145
Hmmmm..... Did you try setting your settings to low? If not, go to options and turn the render distance to short, turn the graphics to fast, and view bobbing off. Also, don't know if it will help, but try turning any antivirus software off and other applications you really don't need running. Use game booster as it helps a lot, I use it for Minecraft as well but try shutting more applications down and using game booster.
all my settings are on low, but it still lags abit :/

