Short or Tall grasses? For what situations? Foliage ? Flowers?

Lucius, you will prob have to stop me here but here goes....
Stipa tennuissima is a superb, 60 to 80 cm tactile flowering grass for sun, for free draining soil. It is irresistable; has to be touched! Grow in at least a group of 3. Elymus magellanicus is evergreen and the bluest grass, the bluest foliage plant of all. Acorus Ogon is not really a grass but grasslike......evergreen, adaptable and tough. Grows in water, boggy ground or dry soils. Bowles Golden Grass is all yellow.....foliage, stems and flowers. Eye catching here with astilbes...I grow astilbe Shogun with them here; an astilbe unlike any other with almost black foliage. Some moisture at roots. Again for the more damp areas hackonechloa macra aureola is a stunner....the classiest of all grasses. Another variety is All Gold. Great for pots too....they make mounds that then cascade. Tiny flowers for wildlife and autumn foliage. Not a grass but check out libertias....Goldfinger has white flowers on unique orange/olive foliage. ...
Pennisetums like Villosum, which has large white caterpillar like flowers and Hamlyn are excellent flowering grasses. Superb for wildlife. Medium size. Easy. Deschampsias flower in mid summer...really lovely see through effect with masses of flowers
Taller and charming is helictotrichon....another blue grass, evergreen with beige flowers. Stipa arundinacea is medium height with orange red tinted foliage and an easy evergreen.
Carex Testacea is evergreen with totally unique copper foliage; you must grow this for its colour. buchanii is a taller upright foxy red carex. Comans Bronze has similar colour but sways and moves delightfully in the slightest breeze.
For something esp good in winter is arrhenatherum bulbosum (forgive if spelling is incorrect). This is an almost white grass that lights up the garden esp in dark or shady areas. I like this a lot......grow near a red heuchera or the black "grass" ophiopogon nigrescens.
For some summer fun sow a few hordeum jubatum seeds now......similar to stipa tennuissima but the billowing flowers have wonderful colours of pink, cream, purple when in full sun. Everybody will want to touch them.
Imperata Red Baron has foliage that turns crimson from mid summer onward....superb in groups or as a ribbon feature. Contrast with blue or yellow foliage......
Do you have space for grasses that are tall? Miscanthus varieties are vigorous......variegatus has superb green and white leaves, Gold Bar has horizontal bands on every leaf and Morning Light has a delightful fountain shape. Cabaret has the best variegated foliage I think. All produce flowers in late summer.
Karl Forster and Avalanche are two varieties of calamagrostis I grow......not as tall or as vigorous as the miscanthus but superb mid summer flowering grasses. Avalanche has nice variegated foliage but both have purple/grey/ beige flowers that are enhanced in sunshine. Must have for summer.
The tallest of grasses, stipa gigantea is magnificent......another see through grass with golden swaying flowers. Here it grows to 9' without bullying its neighbours
Ok, these are grasses I grow and enjoy but perennials like anemone Wild Swan would look good too in your area lucius......wonderful pure white flowers with blue reverse from spring to autumn. Different totally from the japanese anemones. Here they attract bees, butterflies and offer contrast to the linear form of grasses.
I suggest you sketch out plants according to colour contrast and shape before you plant anything. Also according to their need for sun, shade and moisture.