Domain prices have constantly gone up until today and they will continue to do so. Why? Every day there are more people who have Internet access, which means that there are more potential buyers online. Just think about the millions of people living in undeveloped countries. They will have Internet access in the future, too. And they will spend their money online just as everybody does.
Dot com has been the dominant TLD for so long, this will not change. Even ccTLDs will not influence the success of .com in any way. Especially because more and more businesses are offering their services to an international target group. Yes, I am talking about GLOBALIZATION. And .com is the only TLD which has been 100% accepted as a global TLD for commercial websites. The other gTLDs (e.g. .net, .org, .info) are also known by the majority of today's Internet users, but they are not even close to being as popular as .com.
Do not get me wrong. ALL domains will go up in value, but especially .com, which is not only THE global TLD for businesses, but .com has also become a symbol for the Internet.
People are going online and their money follows. This will result in higher traffic numbers, in more online sales and higher domain values. Advertising dollars are going from the offline media to the Internet, as well. Online advertising spending in the US is expected to be about $17B this year and about $30B in 2010.
After all, I would say the future looks... promising!