If you have a really great dot com for resale, you should register as many other TLDs as possible.
What I am talking about is showcase domains. For instance, I have Domain Hostmaster .com/.net/.us/.info, but I wanted Hostmaster .com/.net/.us/.info
Hostmaster.com is owned and is offered for sale by one guy on sedo. The .net is owned by another guy, the .us is in another guy's possession, the .info belongs to yet another guy.
In order to get and secure one showcase domain I have to deal with 4 different sharks. Just the idea alone of not being able to secure one of them would break the brand. The expense of going after 4 or 5 or 6 TLD is frightening.
So, I just haven't bothered. I know the name is worth more than I can afford. Securing the name as a TM is absolutely scary because if one of the different 4 owners decides not to sell (in the primary TLDs that I am concerned about), I have a dead investment.
So the owner of Hostmaster.com shot hisself in the foot by not aquiring them all. I mean, it is a showcase name, why would you not protect it? Certainly, some giant hosting company might be able to afford this mess, but only a corporation can now. By not protecting this name it is almost unsellable because a corporation with deep pockets can make a name out of anything decent.
-My 2 cents.