Funny, how the only Safety Item which contacts the road is the one item we all like to skimp on, me included. Buying tires is an expensive and sometimes a confusing task. Generally speaking better quality tires will be easier to balance and closer to being perfectly round. Yes all tires appear round but I have seen new tires that are all out of round and hop and cause noise and develop bad wear pattern (cupping and feathering). Know your self, if you never get your tires balanced or rotated do not waste your money to buy quality.
Buy the proper size and load rated tire. Many times people by a car tire for a large suv, which should have a LT tire (Light Truck) because the are less expensive. Ultimately they will not wear properly and decease their projected lifespan. Traction rating is important to some people, and usually the higher the traction rating the less mileage you will get but they will get more traction and will be quieter.
To get the most from you tires lives, keep them properly inflated and rotate all four every 10,000 miles.