If you are lucky enough to find fresh golden beets at a farmers market - grab them! I'm not sure they taste much different than a red beet but they sure are beautiful on the plate! This salad can be served cold or warm - I prefer it warm. You can always do the beets ahead of time and give them a quick zap in the microwave before assembling.
I used this same dressing for roasted root vegetables in the fall and winter. I simply roast parsnips, fennel, whole garlic, brussel sprouts, sweet potatoes and red beets in a hot oven until tender, toss with dressing and toasted pumpkin seeds and serve (omit the feta). I typically cook my beets separately and then add just before serving so they don't turn everything red!