Of all the greeks, vega is probably the most important, for it influences delta and gamma. Theta is probably second. I use a couple of ways to predict volatility. First, I take a look at the IV's of ATM calls for the front month and for a couple of months into the future (for example, I am now looking at the JAN, FEB, MAR ATM calls). If the IV's are increasing, then traders expect volatility to be flat to lower. If IV's are increasing, then traders except volatility to rise. Next, I look at the absolute value and direction of the VIX. This analysis seems to confirm the results of the IV analysis. So, choosing a "short volatility" option strategy seems to be the way to go. If, for some reason, you except volatility to sharply rise at this point, then go with a long volatility strategy like long straddles, ie. The analysis says otherwise. Here's the problem: If you choose straddle, strangle, iron butterfly, or iron condor, and the underlying takes off, then the directionality of the underlying will kill you--believe me I know. You gotta be right about volatility and direction. For example, during the March 2009 cycle, I used the iron condor strategy, figuring the early march drop was the top of the VIX. Well, the Mar bull put spreads did great. Unfortunately, because of the incredible rebound, my bear call spreads got killed and I lost money on the trade. Same thing happened to me in the September cycle. In March, what I should have done is exit the short calls at the bottom, and then let the short puts ride. September was a problem, for the market just took off--there was no profitable place to cash out the short calls. (I trade futures options on the S&P 500). Obviously, if I simply traded bull put spreads in both cases, I would have been a winner. Hope my experience helps you.