It's not showing up there?
hmmm...
what I see under QUICK LINKS (Top left corner)
BROWSE
POWER SEARCH
ACCOUNT
BUY iTUNES GIFTS
REDEEM
SUPPORT
MY ALERTS
COMPLETE MY ALBUM
In iTunes 9, mouse over the MUSIC tab up top and click on the arrow. You'll see iTunes Essentials right under Music Videos.
Also, if you're on the Music landing page in the store, you'll see a box in the upper-right corner (Music Quick Links) and Essentials is at the bottom of that link. Also if you search for pretty much any artist, if they're on an Essential, that will come up on the side as well...