We love our eBags Brand EXO 2.0 Hardside:
http://www.ebags.com/search/b/ebags/bc/exo-20-hardside.
Our household has four of the EXO 2.0 Hardside 24" Spinner, and two of the EXO 2.0 Hardside Spinner Int'l Carry-on Mobile Office (which on a recent flight on a smaller plane with VERY small overhead bins I discovered actually fit under the seat in front of me
).
They are lightweight, made of polycarbonate and thus can take quite a beating -- our so far have no visible damage to them despite multiple flights with multiple legs. I find they move really well over almost all surfaces (thick pile carpet they will go over, but you have to apply some downward pressure on the handle as you roll the bag -- a bit of experimenting and you will find the right amount and once you get the hang of it it will move well over thick carpet too). I have gone over thick carpet, thin carpet, tile, other flat surfaces like roads and concrete, cobblestone, brick, and some other surfaces.
I have found the 24" to be a really nice size: eBags designed it the size they did to make it very hard to exceed the 50 lb limits. I have found this to be the case -- fully packed ours is usually in the 25-30 lb range; once I got it up to 37 lb when i had to put textbooks in it. The bag empty is quite lightweight. Finally, I absolutely love love love the 4 wheel spinners and to be honest it will be a very long day before I would go back to older style luggage with just two wheels
Oh ! And the integrated TSA-friendly lock is appreciated - I have lost track of how many TSA padlocks I have had "lost" or damaged and replacing them gets old and expensive.
The final tidbit is that eBags has a great warranty for their brand items: lifetime warranty, exchange or return (they call it "whatever it takes").
I am a big fan of the eBags brand and have a bunch of other items from them: purses, packing cubes, bags.
Hope this helps.
SW