I've been using Rainbow Spiral Supports ($34.95 for five) for the past several months in my garden, and have found them to be a useful tool. While they're originally meant for tomato plant supports, I've found that they work well for any vining plant.
To hear more about the spiral supports, and to see how I'm using them, read more.
Currently, they're supporting some trellising pea plants. At five feet tall, the rainbow spirals are doing a good job at supporting the quickly growing plants, and while the peas' tendrils aren't quite convinced that the smooth metal is the best thing to latch onto, I've been able to encourage their attachment by winding some wool yarn around the spirals.
I also appreciated the ease with which I was able to work the supports into the soil, since the spiral shape can be twisted easily and driven into the ground. If I do use these for tomatoes as well (which I likely will), they're also better than tomato cages, since they don't take up as much space. This is a definite plus for small garden spaces such as mine. And it doesn't hurt that they're nicely designed. I'd much rather look at a brightly colored steel spiral than a tomato cage!