> can someone explain to me why deflation right now is a bad thing?
Basically, inflation is bad... but deflation is deadly. Simplifying things a bit, when deflation is rampant, the best investment you can make is to sell everything you own, then hide your money in a safe. The problem is, money hidden in a safe is money that's not moving around and fueling the economy. Stir in wholesale deleveraging, where every dollar hidden in a safe ultimately translates into tens or hundreds of dollars removed from the larger economy, and it's not hard to see why sustained deflation causes an economy to implode and self-destruct.
Deflation is deadly in other ways, too. If consumers get used to prices endlessly falling, they'll start to defer big purchases with the expectation that they'll be cheaper next month. Stores cut way back on products, because it's too dangerous to keep items in stock. Items that are genuinely good end up failing commercially because products that suck cost 10% as much. Think about the frustration you feel when you go to McDonalds ready to buy a Big Mac meal, then discover that double cheeseburgers are on sale for 29c. You really want a Big Mac, but you can't bring yourself to pay $2.99 for one because you don't want one THAT badly. When that phenomenon spreads to the economy as a whole, it poisons the entire retail ecosystem and ensures that the only products that survive are those leading the race to be the worst and cheapest.
What about industries where falling prices ARE the norm (computers, cell phones, etc)? Think about it... prices per unit of power have plummeted, but overall total system prices have either fallen slightly, or INCREASED. In 1999, I paid $200 for my first cell phone. It made voice calls. In 2008, I paid $299 for my current cell phone... it has a faster CPU, more ram, and more persistent storage than the laptop I bought 4 years ago. In 2004, I spent around $700 buying a motherboard, Athlon64/X2-4800, 2 gigs of RAM, and a 250mb hard drive. Last month, I spent around $800 buying a new motherboard, a core2quad Q9400, 8 gigs of ram, a 250gb 10krpm Velociraptor, and a 1.5TB 7200rpm hard drive. Way more value, but each PC ultimately represents a more expensive total purchase.