The key question before we start is will the plants be watered on a regular basis ? and another point is soil type, now heres a few tried and tested plants that i have growing in large pots/containers and which do extremely well, here goes, Bamboo, Aurea and Nigra and Fargesia these are clump forming and do exceptionally well in pots, you could opt for large potted displays of perennials which look fantastic plant so you have interest throughout the year, other plants that do really well are types of conifer eg Thuja, gold or green, juniper, tsuga, if very large planters are to be used then plant some heathers around the conifers, spring,autumn,winter flowering, looks great, plant with ericacious compost, other plants that do really well are Lonicera baggesons gold, Spireas, viburnham tinus, Skimmia, there are so many more, two of my special plants for planters are Sedum spectabile and the beautiful hardy geranium Rozanne which will flower its head off for many months, so many more i could mention but like i say they will need to be kept watered.

Our neighbouring village has planted some ground cover roses in large concrete troughs. They have been lovely all summer without a lot of attention. (My Rozanne did its stuff last year but this year has only just decided to start flowering!)

Acers (in ericaceous compost) will look wonderful, and no care needed. Another possibility is Indigofera.

Check out the neighbouring villages for what you like/ don't like about their displays - I'm guessing that there's a Best Kept/Beautiful Village competition in your area and you could get inspiration from this year's contestants.