If you're planning on upgrading your old gaming monitor for something a bit flashier, you could do much worse than the Acer Predator XB271HU. It's currently on sale for £489 on Amazon and has a listed saving of £210—though in this case, £100 is probably nearer the mark when taking the historic price into account.
This 27-inch IPS panel comes with a 2560 x 1440 widescreen resolution along with with a 144Hz native refresh rate (overclocked to 165Hz) and a 4ms response time. Full G-Sync support will allow the monitor to line up with your in-game refresh rate and further limit the chances of tearing, when paired with a GeForce graphics card. The flicker-less and blue-light filter technologies also help to reduce screen flickering that can cause eye strain during longer gaming sessions. This model also includes the usual ports such as an HDMI, a USB, and a DisplayPort.
Acer Predator XB271HU | now £469 (save £210)
This 27-inch IPS monitor offers a 2560 x 1440 widescreen resolution and full G-Sync support giving you a crisp display without the cost of a premium panel.