What direction does it face? All sun, part sun, all shade?
For low water or drought tolerant there are a lot of other choices than succulents.
How big is the area?
Is it possible to post a pic?
Do they have a preference on flower color etc.
So many choices with such a generic request can't recommend anything at this time.

Start looking thru the Western Garden Book for ideas.

Tough as nails, all-too-common, boring, quick to form a dense screen, and utterly, completely reliable: Ligustrum japonicum, available at any big box store.

I second privets. I don't think they are boring.
They are lush and gorgeous when they are left unpruned, and they don't need water. They will grow in sun or shade, and they have a decent growth rate. They get pretty flowers, they don't leave a lot of litter. There are darn good reasons some plants are ubiquitous.
Renee

There are darn good reasons some plants are ubiquitous.

Amen!

Speaking of ubiquitous-

How about Iceberg roses? Mine is seven feet tall and blooms from top to bottom for most of the year.

Renee

Here is a link that might be useful: Hoovb on the Holy Trinity: Privet, Iceberg, Olive