Grey is a wonderfully neutral and interesting colour, but I'm beginning to think that some shades - or at least the greys used in some applications - are too trendy to last the long haul. Dark grey or blue-grey kitchen cabinets, for example, may look great now, but I have a feeling we may tire of them a few years down the road (I'm a big fan of the classic white or light wood kitchens that will never go out of style). Also, blue-grey rooms can risk feeling cold and stark if you don't layer them with lots of natural warm textures and colourful accents.
That said, a light misty neutral grey or a grey that's slightly on the warm side - aka greige - can be timeless and the perfect neutral backdrop for either colourful accessories or muted soft decor. Greys work really well when designing a calming, soothing space, and they're a wonderful alternative to white walls. A cool or pure grey will do a great job of neutralizing overly yellow or reddish wood floor, cabinets and trim. Warm-neutral greiges will liven up a north-facing space or a room with low light.
You absolutely need to test different greys on your walls to see what will work in your space, because it can easily end up looking too cement-cold or dingy and dirty. Depending on where you live and the light that you get in your rooms, grey will look very different in your home compared to another, and in morning vs. evening.
HOWEVER...as I preach with everything in design and decorating, keep it simple and don't overanalyze your colour choice. To make that easier, I've put togther this guide to help you choose the right grey paint. These tried and true- go-to shades of grey below will work well in most rooms and will outlast the trend.
I use Sherwin Williams paint for a lot of my projects and Repose Gray is an all-time favourite that works in pretty much any space. It's a neutral with a teeny bit of a warm undertone so if feels good even in low light. Here's Repose Gray and some other Sherwin Williams greys I really like.
I've also used CIL Oyster Bay with great results, like this kitchen project in Calgary where the colour was used to neutralize the yellow wood cabinets but still add a touch of softness.
Benjamin Moore has lots of wonderful greys as well, including my favourite, Misty Gray. I've used this both in open spaces with tons of light and in basements with low light - the colour came out very clean and true every time (sorry I don't have photos of it). Its very soothing to the eye.