I am based in Ireland and looking to buy a 27' 1440p monitor from e-bay for gaming, light office work and movie watching. I am choosing ebay as it is ~50% cheaper than local e-tailers. I am a gamer but too often FPS so 60Hz is absolutely fine. I currently have gtx 660 and have a second one on the way at a very good price for SLI. I have a budget of up to about 300 euro. I have limited brand preference and am open-minded.
This would be a single monitor primary display I think.
I just bought that very monitor, actually. The zr2740w is hands down the best deal for a 2560x1440 monitor right now. The korean brands are both lower quality and have substantially worse support (though I don't know how HP warranties refurbs).
The only things to consider are that it has no onscreen menu, so all you can change is brightness and input source, and getting the displayport connection to work may be a pain with some hardware (though the dual link DVI port should work with everything). Other than that, input lag is nearly zero, response time is average for an IPS panel, image quality is top-notch, and the anti-glare filter isn't very aggressive. HP recently introduced a replacement for the zr2640w (the z27i) so retailers are selling out the remaining stock of the old model at crazy low prices.