A couple of takes regarding this from a programmer (who, naturally, is extremely neurotic about his skills):

• There is no single skill that defines your value
• You are probably not even aware of all the things you excell at, because these things seem the easiest to you
• Social intelligence is extremely important. You can’t do shit alone, and even if you can, you need to sell it to someone
• You don’t need to be the best to be extremely good at something. Being in the top 10% means there are countless people at least as good as you, yet 90% are worse
• The hardest things require a good team, not a good person
• A good team is more than the sum of its parts. Supporting some genius can make you 200% as productive as you would normally be, because they can direct your skills to the right places at the right time, or clear roadblocks that woud take you forever