The ultras are good for daytrading and short-term swing trading. Other than that, they only work if you have a strong low-volatility trend in your favour. Check out the longer term charts for the various bull/bear pairs. In many cases both are down - you lose whether you are right or wrong. You also have to be careful with "distributions" - they hit you with tax consequences. Most of that happens in the fall, but it's something to be aware of.

When the time comes, you may want to consider VXX - it's a play on volatility. Theoretically, it should move up when the market moves down, but I haven't really researched it yet. It may have pitfalls similar to the ultras.

Another possibility is to simply buy puts on stocks you think will drop. You know exactly how much money you stand to lose if you are wrong.

Personally, I plan to raise as much cash as possible, and take a long vacation. Spring and fall are often market turning points, and I think there will be a powerful rally starting in the fall - perhaps even the beginning of a PM bubble - I want to be well rested for that, lol.