In my case choosing the title of my first book was a much harder exercise than picking a domain name for my web site in 1997. As a writer who has learned to trust my instinct a lot more than other things the name 'italk4u.com' came instantly to mind. It was available and registered within 24 hours. Since then others have gone down the same path and put up domains with similar titles.
The main thing is what you want that domain to do for you. If you are registering names to flip sites it is a lot different to developing one with information along the lines of one's expertise. On the other hand, business sites usually follow the business name and they are usually available if unique. Some adjustment may be required if others have a similar name.
Along with the '.coms' there are also '.nets' and also others that may be followed by your country id. For instance, in Australia we have '.com.au' and that makes a lot more titles available than would otherwise be.
My area of expertise is spirituality and research into the origin of language and religion. This allowed me to highlight it on domains with other names, such as mountaintalk.net. This fits the fact that speaking on the Internet is a lot like talking from a high mountain so the rest of the world can hear it.
Picking names that best suit the individual is not difficult if one follows some rules. Don't try to be smart with the name and simple titles are always more appealing. One does not want to deflect from the message by complicated numbers and other things that are hard to remember.
Follow these guidelines and enjoy your time on the net. One can easily build up friendships and write emails, blogs, and articles to support your work. In the end it does pay off.