It’s always intriguing to see new produce options available- some are dictated by consumer habits (see below post on seedless watermelon) and some are shaped by other forces (more on that in a later post!)
Whether the addition is simply for more consumer options, for mass distribution for growers, or a contrast for the culinary on plates, new choices always seem to slip into availability. I hope for the day when even more local/specialized food options are available in food stores. See the following on red celery:
http://news.yahoo.com/s/ap/20101016/ap_on_re_us/us_red_celery
Picture repost from article- Duda Farm Fresh Foods
Greenwordchef's Blog 
There’s an heirloom celery called “English Red.” I think consumers have just become accustomed to seeing only one variety of certain vegetables. The celery we buy in the supermarket is probably a variety that ships and stores reliably. My garden celery (green, “Tango,” I think) didn’t do so well, but I used it anyway to make the most delicious stock ever!