I'm considering getting some new luggage, and am wondering how y'all make the decision between cost and quality?

How much are you going to travel? If it is occassional recreational travel, I would go with discount luggage. I have generally gone this route, and even though I travel alot for work (frequently weekly for most of the year) it has held up pretty good. However, it is not as good as the higher end luggage such as Samsonite or Tumi. I have zippers break, or some of the hard plastic lining inside the luggage, etc. If you're willing to put up with that, then its fine., and if you only travel occassionally, you may not even see such issues at all.

Skimping on luggage is like skimping on shoes. I've never regretted buying a good set of either. I've really really regretted buying cheap luggage. You don't want your bags to fall apart when you're in the middle of traveling. You want to be able to sprint through an airport nearly as fast as you would without bags, with your four-year-old comfortably riding on top of the suitcase. I praise my Samsonite bags every time I travel. The one time I bought a very cheap suitcase from a vendor in Korea, I cursed it for the five days it 'worked' during my trip. On the sixth day a wheel fell off.

It's a good time to buy if you have the cash, because there seems to be an abundance of luggage sales. But even Samsonite can make some shoddy bags these days (typically imported from China). You have to really look at the construction carefully. Also, good price doesn't necessarily equal cheap construction. I bought my best suitcase for 140 dollars on sale about fifteen years ago (in today's dollars I'm not sure what that would be). That thing has been through A LOT and still functions perfectly.

There's two schools of thought:

Buy really cheap luggage and throw it away at the end of each trip.

Buy really good luggage (Samsonite, Wenger, Flight Case) to use for a lifetime and then give it to your children.

Before our family trip to India over Christmas, we bought a decently priced set of Pierre Cardin luggage from Amazon. It held up well and best of all, we were able to purchase brightly colored suitcases that were easy to pick out of the baggage claim (a big plus as frequent travelers know!). I figure if the bags held up through being checked all the way to Delhi and back, plus being lugged around India on trains and buses, they're pretty good.

I'm all over the board on cost / quality, as long as you don't go way cheap. Some of the "designer" stuff like quarkhead mentions seems to be fine. I had a really expensive Briggs and Riley when I was globehopping, and it did ok for a while, then it didn't. A lifetime warranty doesn't mean much to me when I have to keep shipping it somewhere for work, and can't use the suitcase. I won't be willing it to my children in any case.

I get whatever bright color I can and spend kind of mediumy prices - look for good brands from last year at places like Marshall's or Filenes.

I always have to have a good rolling carry-on for short trips, so I did a mileage calculation on my carry-on vs. the bags I check. That carry-on has to have good wheels, so that's where I spend the money. It's about 100:1 in terms of carry-on wheel miles vs. my big suitcase.