It is my unwavering opinion that everyone should try to buy their own name dot com. I have crisnoble.com. My wife (girlfriend at the time) decided to take on my last name because angelanoble.com was available but angelajones.com was taken.
Most people do not realize how easy and cheap it is to buy a domain [1]. I tell my friends from college it costs about two packs of cigarettes to own your own piece of the enormous digital pie that is the internet. To my family, I tell them it costs the same as a fancy burger. All told you are going to spend about fifteen dollars per year per domain [2].
There are many different companies to buy domains from, these are called registrars. Some registrars that I have used and can recommend are namecheap, iwantmyname, and name.com. Iwantmyname.com probably has the best search interface and looks for every single TLD known to man (see below).
No matter which registrar you pick (just do not use godaddy [3]), a .com domain should cost between $9-12. Be sure to avoid add-on features like privacy guards, three-page web page creators, e-commerce shopping cart plugins, and ssl certificates (unless you know what an ssl cert is, in that case you can make a judgement call). When in doubt, leave it out.
If you are having trouble coming up with a domain that you want to buy or if you find that cool.net is already taken, there are several websites dedicated to helping you find or refine your domain name. I use the awesome domai.nr all the time. It suggests slight variations on your name and different domain endings. BabySquatter is a similar concept geared towards reserving an actual name.
[1]: Warning, after reading this you may find yourself compulsively buying domain names. It is my advice to wait at least 24 hours before buying that awesome domain name that you think will turn into the best business idea ever. Don’t worry, it will still be there tomorrow, and once you sober up you might realize it is not quite as good of an idea as you originally thought. That being said, I never listen to that advice and am the proud owner of ten or so domains that will never be used but that I renew every year “just in case”.
[2]: Unless you want a fancy pants TLD like .ly or .io, then it may cost more.
[3]: The reasons not to use GoDaddy warrant a blog post of their own. In a nutshell, the CEO kills elephants for sport, they objectify women in their ads, have dismal customer support, have terrible user experience issues, wrote the book on dark patterns to up-sell needless add-ons, and to top it off they support terrible freedom restricting laws such as SOPA. If corporations really are people, then GoDaddy is Joffrey Baratheon, and nobody likes him.