The BenQ XL2420G as mentioned above is good, but it is only 24" and a bit pricey for that size.
The Acer XB270H(
link) is in my opinion the best 1080p 144hz g-sync panel. I actually ordered on last week and it should arrive tomorrow. I could post back here and let you know how i like it later this week if you'd like?
I picked it up on amazon for $350 refurbished directly from Acer, and they're still selling those as of right now. They're closer to $500 new from amazon. Only drawback is it is a TN panel, but it is 1ms so I think that makes up for it.
The more expensive Acer XB270HU is a 1440p 144hz G-sync panel. It is also IPS, unlike the 1080p counterpart. If I had the budget for it, I would've bought that one, but at $800 I just can't.