When I lived at home (in suburbia), shoes mattered slightly less to me. Don't get me wrong, I've always been a shoe person. And I've always been a big fan of comfortable shoes. Being a nearly flat-footed person, I don't normally like heels since they hurt and stretch the arches of my feet. On a day-to-day basis I wear flats, or boots in the winter.
But when I moved to the city, I became acutely aware of how important shoes were to me and to my (poor) feet. You walk a lot in the city. You need comfortable shoes. For example, I had owned a pair of rain boots for years in the suburbs. When I moved to the city, I wore them so much that they broke in only a couple of months. I used to own only one pair of tall boots. In the course of one winter, I wore the heels down so much because I needed to wear tall boots often to keep my legs warm.
You have a couple of options: take really good care of your shoes (conditioner and polish for leather, and lots of trips to shoemakers), try not to wear them out a lot (which means owning a lot of different shoes), or keep buying cheap, throw-away shoes. So here's my advice: get lots of comfortable, well-made shoes. This doesn't mean they have to look like your grandmother's shoes (see also: Easy Spirit). There's tons of comfy and stylish shoes out there. Here's a list of all the best/most versatile/comfiest shoes I own:
A pair I thrifted in the West Village for $20 that have lasted surprisingly well (I got the heels replaced once)
BDG (They no longer sell those at Urban Outfitters, but they're my favorite boots, I wear them nearly every day; they zip up the back!)
Hunter (I don't currently have these but I'm getting them for the holidays as a present; don't gawk at the price tag, my friend has them and they're SO worth it)
Bean Boots (These are the warmest boots ever and they keep your feet so dry; don't be afraid to jump in some puddles or snow piles)
Converse (These have held up for years at every intense GA standing-room only concert I've been to, including multiple Warped Tours, so they're pretty reliable)
Keds (Great summer shoes, lightweight and comfortable; make sure you get the right socks to go with them though, because they're cut low in the front)
Plimsoll sneakers (I wore these every day for a week of intensive walking in Montreal; beautiful and cheap)
Flats: I own almost an unlimited number of flats and I will not mention them all here (especially because a lot of them are old and hard to find online) so here's some of the highlights
Jessica Simpson (Basic black flats can never be wrong)
Dr. Scholl's Foldable Flats (For those nights when you just want to take off those heels; it even comes with a case so they're easy to carry around with you)
Happy Feet (I got these as a Secret Santa gift and they are the greatest, most comfortable, most obnoxious slippers ever created; I love them and I always get compliments on them)
And don't forget shower shoes. I use Old Navy flip flops (they're like $2.50).
Invest the money in shoes. Seriously. You'll be glad you did.
P.S. If you find shoes you really love but you're worried they might not give you enough support, try shoe inserts by Dr. Scholl's. They make products for nearly every type of foot pain (seriously). They'll work miracles for those really cute heels.