As a sustainable advocate, I would always prefer to use an aggregate as these allow for natural penetration of any rain that falls on site. Complex drainage systems aren't required to take runoff from the paved driveway and so the end result to me is not only totally sustainable but is cheaper. And if you plant trees down the side of paved driveways, the paving or cobbles too often lift and become walking hazards. Burglars also don't like aggregates!

For tropical plants try crab claw or gingers for the height to screen the fence and little flashes of brilliant colour. They tend to grow upright rather than outwards. They can be easily cut back without looking scrappy. I'm also thinking of perhaps mother in laws tongues and/or moses cradle. These two are very hardy and pretty cheap plants that can take the odd running over with the car... one thing I've noticed about driveway plants is occasionally someone runs them over! You could space the larger gingers a few metres apart and then fill in the rest of the spaces with the smaller plants. They also reproduce and you can fill in any gaps from accidents with babies from other plants. They also can all handle the hot hot sun and don't bush out. The gingers can come in variegated foliage and I think would have a better coverage and shape than cordylines.

Not that I know a great deal about plants (yet) but you may want to include what your climate is and location (shade of a building part of the day or direct sunlight) as this will effect peoples recommendations. for our area (hot sun, sandy soil), we are going for Crepe Myrtles and screens of jasmine and passion fruit vines for narrow spaces.

there are way too many colours going on here. Your home is a traditional style and yes the cream and green are traditional colours with the reddish brick however why did you put grey around the windows??also you have red scollops above the grey and it doesn't do the house justice. What colour was there before you painted the grey?? considering grey is a more modern colour I think you were attempting to modernise the externals. in saying that the roof would have been better to paint charcoal the cream in white and then the grey and then the driveway would be done in a grey stain. but if you leave it the way it is and cover the red scolloping above the windows the same grey and the bricks below the windows near the ground grey as well then get the drive way restained to the reddish colour of the bricks on the house and then it would blend more and look inviting.