We got a blender (Vitamix S30, most of the cost covered by a company long service award voucher) a few months ago. Definitely a top quality item and one we're already using regularly for smoothies and soups, and plan to use for other things as well (next ideas hummus, almond milk as trials, could become regulars if successful). Also got a non-stick oven tray, which has impressed in its first couple of uses. It's not really a revelation in itself but should mean we use much less greaseproof paper, so over time will pay for itself multiple times over.
In terms of ongoing use, two good chef's knives and bamboo chopping boards are staples. At one point I thought that a high-end non-stick frying pan was really important, but actually we have a standard-price (but not really cheap) one that we use on average once a day and after two years it's still like new, showing that for these kinds of items if you look after them they will last.