I hate my garden! Advice on things to plant?

[pinkhyena]

Actually to be more specific I hate the borders. They're about 2-3ft deep, one is approx 7 ft long and the other is about 10ft. There's some things that have established really well (clematis, roses, a rhododendron and hydrangea) and bulbs that come up every year but the rest of the borders look shite. I need some perennial bedding plants and a few bigger things...possibly something a bit prickly to deter next doors cats from crapping in the beds!

Any suggestions for things I could plant that are relatively cheap? I hate looking at my garden right now all the bulbs are dying off but there's nothing to replace them right now.