I'm a huge fan of Briggs & Riley. Quality is top notch, and it's also one of the few brands that offer lifetime warranty that includes airline damage and are often recommended by luggage repare shops for being easier to fix. The downside is that they're definitely more expensive. Otherwise, I'd go to Travelpro which is good quality too but for a lower price, just not as good quality as B&R.
For a trendy brand, I'd look at Away. They just released their soft side luggage that's expandable.