Caution guys (& gals), I don't think .mobi is going to take the mobile world by storm overnight. With the average person only changing phones every 2-3 years, it could take some time before the .mobi becomes a default extension as in being added to software and default mobile search lists. I still see a lot of names that I really don't think will ever sell on a secondary market in the first couple years. The .info and .us TLD's each took about 3 years to mature as well. I think to have any short term value (less than 3 years) I'm using the following rules.
1. Would a person who is mobile search for something under this name (generic is probably the best bet). If a person would or could wait until they get home, they probably will. Things like movie times, restaurant/hotel directories, weather, sports scores, address lookups, and immediate needs probably have the most value.
2. Is it short enough to type on a 10/12 button phone? Hyphens are not fun to type on a regular keyboard. Many cell phones take several steps to find non-alphanumeric characters. I'd avoid long or hyphentated names unless you expect them being found in a mobile search engine. How many actual keystrokes does it take on a 10/12 key phone. Just typing ".mobi" until it defaults in software is 10 keystrokes (1,6,666,22,444) (if they'd picked .WAP as the TLD it would only have been 3 keystrokes)
3. Is there a customer for the domain? If you don't plan to develop yourself, then who would buy the name? If the list is short or the potential users would use another name like their brand name, you may not have a potential buyer.
I do think .mobi will have some sucess, as it will likely be forced on us by the mobile industry. I just don't think it will be in the first year or so. On the other hand, the forced two year registrations give two years for it to mature before having to renew.