First, liability coverage protects you in the event you cause an accident and injure someone else. We recommend that you buy at least $250,000 of bodily injury liability protection. Most policies have a "split limit" feature which provides up to $250,000 per injury, and $500,000 total (if the accident cause multiple injuries). If you've accidentally injured someone else, their medical bills can rise quickly and you'll want enough protection. In addition, you should also look into a liability umbrella policy, which provides additional protection on top of your auto policy. Umbrella policies are usually sold in $1,000,000 increments.
Please note that Virginia's minimal limit for liability coverage is just $25,000, which is ridiculously low. If you're discussing these issues with your insurance agent, you should pick the coverage that works best for your needs. However, these figures are minimal recommendations which we routinely make to our clients.