Legs are the larest, most powerful muscle group in the body. As with any other training methodology, you want to work on getting your heaviest lifts out of the way first. So it should be a no-brainer, that because legs are your biggest muscles, they should be employed for your body's hardest training. I believe legs (not chest & bi's) should be everyone's first muscle group, first work out day of the week. Who cares how hard your pecs are - or - how rounded out your delts are -- if you have chicken legs - you're a lawndart. And unless you plan to be the next great star of the NPC/IFBB Men's Physique, you're going to want to train wheels.
But do you need to do squats? In terms of hardcore'ness, the short answer would be 'yes.' But there's so much more you can do to make up for not doing them.
