The trend in .com and .net seems to be downward. I think that this could be the end of the Buy To Park boom where domains were registered purely on their ability to generate PPC revenue. The declining PPC revenue may also have edged the profits on many of the marginally profitable parked domains below regfee. These domains may be dropped over the next year or so. Throw in the restrictions on Domain Tasting and you have the perfect storm for parked domains. Without the availability of consequence free tasting, the domain tasters have to evolve better and more effective algorithms that will identify profitable domains without tasting. Most will not be able to do this and there will be increased competition for these profitable domains as they drop. I would not be surprised to see .com and perhaps .net go into negative growth territory in 2009.
The next domain rush will probably be, to a small extent, .tel but too many people have been burned on .eu, .mobi and .asia TLDs. The growth on .asia is now down to around 5000 domains a month as it has moved out of the landrush phase. The .mobi TLD is currently in the Junk Dump phase and it has lost a lot of domains in November (approx 69K) but there is still demand for that and approx 23K new .mobi doms were added in November. The .eu ccTLD is a dead TLD.
The ones to watch will be the large ccTLDs and the ccTLDs that are in countries that are about to go ccTLD positive. (That's where the number of ccTLD registrations exceed the number of .com registrations in that country.)
Regards...jmcc