I'd second the "don't do gear" advice.
From that pic, and having seen the (clothed) side chest you posted a while back I reckon you could do very well on the natural circuit right now. Anything over 180 lbs (even at 5'10'') is big (real big) for a natural, if you could get to 200 lbs in contest shape (ie: add another 20 lbs of muscle) you could easily compete on the pro natural circuit... and successfully at that: making more money from endorsements and contest winnings than all but the top 30 IFBB pros (and in a few years... all but the top 10 IFBB pros).
At 220 lbs (+40 lbs) in contest shape (assuming you've got and could maintain a balanced physique) you'd beat every other natural currently competing anywhere in the world. Think about it, you're probably four years of successful training (10 lbs a year) away from being the Natural SERGIO.
However, once you take first steroid, you'll have to get to 270-300 lbs (by then maybe even 350 lbs) to be the best.
Just something to think about.
The Luke