Here's Sir Chris Hoy, talking about his favorite gym lift, the squat.  He's doing high bar, where we do low-bar in the 'Haus, but we'll let him get away with it this time .. If youtube is being consistent, the girl he's talking to is picking her nose in the sample shot below, heh!

Here's a diagram showing the different squat variants, stolen from Starting Strength, Basic Barbell Training, 2nd Ed.