Materialistic is the most apt term I can think of:
ma·te·ri·al·ism: a way of thinking that gives too much importance to material possessions rather than to spiritual or intellectual things
The term sneakerhead also comes to mind, but describes nowhere near what you're trying to describe. From the related Wikipedia entry:
A sneakerhead is a person who collects, trades or admires sneakers as a form of hobby. A sneakerhead may also be highly experienced in distinguishing between real and fake replica sneakers.