Significant research has gone into this and tons of info is available online describing the benefits and methods of crop rotation. Here are some publications from UT's Agriculture Extension program:

Disease Control in the Home Vegetable Garden

Crop Rotations

Thanks, Brandon. As usual you provide the most well researched information. I'm interested in knowing what the locals here in East Tennessee have had success with. I know about rehabilitating soil with certain grains or legumes but I hope to hear a success story or two of gardeners who have found other delicious veggies they grew in their old tomato/ pepper beds.

Unless I hear good reasons against, I think I'll try onions, carrots, radishes. If I don't get any relevant replies, maybe I'll be able to partially answer this question myself by seasons end. I'm sure I'm not the first to deal with this situation. Tomato beds go bad, but surely they are used for something?

After all that work digging for our garden, I hate to see it just go to snow peas or winter barley. Thanks, y'all.