Andras Fabian of alpilotx is by now fairly well known amongst the X-Plane community for his donationware scenery and his latest release, New Zealand Pro for X-Plane 10, will only add to that

Completely upgrading the default scenery with much higher resolution mesh, improved landclass, linear features (roads, railways, powerlines) and treelines, the scenery is free to download and try, with the developer only asking for what you think the scenery is worth to you as a donation, in return. Check out the image library, here, for comparisons between the default XP10 world scenery and New Zealand Pro, while you can find download information on the alpilotx website, here.

One thing to note is that this scenery will make you PC work pretty hard – the developer recommends that you run the 64-bit beta version (10.20) with 8Gb of RAM, although it will run on a 32-bit OS and installation of XP10 with 4Gb of system RAM.