ASUS VG259QM and Zowie XL2546K (currently using/testing this one) are definitely my favourites so far.
VG259QM does an amazing job, for an IPS panel, in terms of motion clarity and FPS gaming performance, thanks to its 280 Hz refresh rate, extremely low input lag (slightly below 2 ms) and low average GtG response time (about 2.5-3.7 ms), all that with practically no overshoot (on overdrive set to 60), and it's really cheap for what it offers. Amazing ergonomics as well, wide variety of adjustments, compact design (I appreciate small stands, more room for my mousepad, easier to organise my peripherals like I need them).
XL2546K is by far the best TN monitor I've ever used (and I have a preference for IPS panels, so that's a big compliment), incredibly fast with about 1.7 ms GtG average response time (no noticeable overshoot on 'High' overdrive setting, at least to me), very low input lag (about 2 ms), great features, it's also free from pronounced pixel inversion artifacts (common in TN panels), quite pricey though. Same as ASUS, very good ergonomics and compact design.
I'm trying to decide which one I like more, gonna make a direct comparison in a few days, as I am not sure if paying so much more for the Zowie is justified, with VG259QM performing so well, and because of obvious TN panel downsides on the Zowie, as well as me not really being a huge fan of DyAc, even though I admit it's really good strobing tech.