Roses have a reputation for being high maintenance- and in my opinion it is a reputation that is fairly earned. In San Diego, we are spoiled enough to think that our gardens should be attractive all year round, and winter time bare branch roses are just not very attractive. However, there are a few varieties that I use often and think of as "easy" roses.
My favorites by far are the Flower Carpet roses. These low groundcover roses are usually about two feet tall and two to three feet wide. They come in about a dozen colors now, and they are unique in that they can produce new growth from their roots, not just from their canes. That means that pruning can be done with loppers. Here are a few of the Flower Carpet series (just to warn you- these usually go for about $20 for a 5 gallon, so you pay a premium for them):
One of the standard low maintenance roses is Rosa floribunda 'Iceberg'. It is a rose you see often, and for good reason. It is one of the simplest roses to grow and has a classic look.
I also think that the Lady Banks roses are worth a try. These are climbing or sprawling roses, great for hanging over the edge of a tall wall or scrambling up and over a short fence.
And for the last of my easy care roses: a great smelling climbing rose that is really a classic. Cecil Brunner is a soft pink with a precious flower and amazing scent. It can be trained up and over larger arbors because its canes cane be 20 feet long. This one is a must have for a country cottage garden.
In coastal San Diego, keep an eye out for powdery mildew. It is common on roses that are getting wet from irrigation overspray or damp air from our June gloom.