Plants come in flowering, non-flowering and all kinds of shapes and sizes.
You have tall narrow plants that bush out at the top like Palms or Birds of Paradise. Or you can have low bushy ones like Chinese Evergreen, Cymbidium Orchids, Rubber Plants and Peace Lilies that can be placed on a tall stand to give the same effect.
Plants can be just plain tall and narrow. Cactus work great especially in front of tall windows. Many forms of bamboo can be grown inside. A rubber plant can be grown tall or bushy and can handle lower light areas. Low light vines can be attached to trellises and grown in an upright fashion. Or an ivy can be hung up high and allowed to grow down to create a tall column effect.
Some easy care plants are delicate and lacy like the Ming Aralias.
Plants with large leaves give a tropical feel to a room. Add a few Palms with a large leafed plant and your room will feel warm even in the winter.
You can go for a more modern, exotic look with orchids and bromeliads. Both of which can handle low light and add color. Move the orchids outdoors to a sunny window after they bloom and bring them back inside when they get ready to bloom again. and Sago palms both grow well indoors and provide a more modern and exotic feel to a room.
Flowering indoor plants tend to be small and are best used as table center pieces. I can spend $15 easy buying a bunch of flowers at the grocers that will last a week in a vase. Or I can spend $25 for an orchid or $5 for an African violet and each of them will bloom 1 to 3 months. The orchids are far more dramatic than the vases of flowers. The African violets come in colors to match any decorating scheme you can dream up. Bulbs can be forced year round just by keeping some in a paper bag in the vegetable bin of your refrigerator.