Practicality and maintenance are some of the key factors to consider in addition to the aesthetics. There has been a huge rise in popularity for timber cladding such as cedar and larch or even charred timber. However, being organic materials, their colour will change over time on exposure to sunlight and rain, and this will not always occur evenly across the wall or elevations.
For wall coverings natural stone has always been popular and there are now a range of stone wall effect cladding systems that are quite easy to apply to a block wall, and look great. Similarly, there are now composite manufactured panels and boards that look like timber but do not fade or suffer any change over time. The options available are both exciting and bewildering so take time to collect images and details of facades that you like.
Beware though that your choice of both roof covering and façade could have a significant impact on the design of the external wall during the build and may even require additional structural supports, e.g. reinforcement for the foundations, so this needs to be decided well in advance. The location of your home is also a critical factor as some facades and coverings may not be robust enough to withstand a coastal location, a north facing elevation or one that is particularly exposed to the elements (wind/rain/snow), for example.