Yeah, walnuts are a nice addition, but sprouts solo are dandy. They should be cheaper at a FM, when I bought them last fall they were just a couple of bucks for the whole shebang, compared to $5 for a whole plant at the store. They're amazingly resilient to a wide range of temps, so I will go with anywhere from 350-400 depending on how long the rest of dinner will take.
Also, try just separating the sprouts into individual leaves, toss with olive oil, S&P, and roast until crunchy - variation on kale chips. The loose leaves that flake off when I roast halves, can't keep Mrs. F.'s greedy mitts off them, as soon as they come out of the oven she's hovering.