Challenges that we face today ( in no particular order):

- high energy costs
- global warming
- rising food prices
- lots of hungry people in developing countries
- lack of business models for social networking
- international terrorism
- war in Iraq
- shifts in global economic and political power ( from US and Europe to Asia Pacific)
- low us dollar
- financial crisis
- budget deficits in the US
- growing number of people with no medical insurance in the US
- slowdown/recession in the US
- etc.

Wonderful times. All these crisis, problems, and challenges mean that for a while there will be sustained demand for new technology developments and problem solving. Most likely, innovations will come from individuals and small companies, rather than large corporations. A great time to be an entrepreneur or tech investor in the US. The country still has the best research universities, VC infrastructure, and good demographics. Full steam ahead!