Window box recommendations please?

[FierceMamas]

New home (rental), I have 2 outdoor window ledges I'm looking to brighten up with a rectangular window box. I need plants that are low maintenance / easy to keep alive. Preferably bright or beautiful.

Ledge 1 = front of the house, south facing gets day time sunshine
Ledge 2 = permanent shade in sheltered walled courtyard

Currently the south facing one has some dead lavender. I don't know if it's dead because previous tenants didn't care for it or if the spot is unsuitable.

Bumping

Monty did a sunny window box and a shady window box on GW a couple of weeks ago. Episodes 6 and 7 if you can find them on iplayer
he did prostrate rosemary, ornamental garlic, and nerine bulbs for the sunny one
and Lily of the valley, ivy, begonia “cascading white” and bacopa for the shady one

There are lots of options for sun and shade - can you say a bit more about your taste / style preferences (cottagey, mediterranian, sleek and modern, exotic looking, whimsical, etc.)?

I have a south-east facing, very sunny balcony with window boxes and low-maintenance plants that have done well over the years include geraniums, petunias, dianthus, sweet potato, dichondra argentea and plectranthus coleoides. All of these are pretty popular in Bavaria, the home of opulent colourful window boxes.
They will need regular watering and plant food, but don't mind hard water (which can be a problem if you have to use tap water) and will flower from May all through to October. If your window boxes are more gerously sized, oleander nerium or hydrangeas (not all of them are suitable for full sun) are also good options.

Some more pictures....