.com and small ccTLDs.
No new GTLD will be the next domain rush in the next 20 years. Nearly every Fortune 500 business is on the web, the web is worth over a trillion dollars accumulating to our GDP in the United States alone, how can anyone even think there is going to be something that replaces .com is beyond me. It won't happen probably in next 20-100 years.
Secondly, all CCTLDS such as .tv that are used for "television" aren't worth anything either IMO.
Only CCTLDS that are worth something are of developed countries that actually use them: .de, .fr, .it, .cn.
.COM is and will be here for decades. I don't understand why it even would NEED to be replaced in the first place. It works perfectly. There is absolutely NOTHING wrong with .com domains.
.MOBI is a failure. You can launch mobile sites from .COM which is more recognized. No reason to re-invent the wheel. Three different letters will not change anything. .COM Is recognized and will be impossible to replace. That's like replacing Google.com with the same exact search engine under a different domain. It makes absolutely 0 sense.
Sure there will be domain land rushes where you can make money for a few more years - until everyone realizes that every land rush is just a money grabber for those that are able to take advantage of the short-term situation.
It's been years where all these land rushes have failed long term. You'd think the domain industry would be smart enough to learn by now not to buy junk.