Oh, no watch out for the Old Trek Cult!! Don't get suckered into spending $2,000 for a 30 year old, 30 pound bike.
I'm just joking of course-- there's nothing wrong with older Treks, riding them, or spending obsene amounts on them. They are good bikes, part of American culture and part of lost youth for some of us. I love old Treks.
But honestly, a shiny new 520 is better bike, often cheaper in the long run. But if you want to go vintage, don't let that stop you. Have fun. Old bikes are full of joy.