Dotster.com — This registrar provides fairly cheap domain prices ($15.75 plus 20 cents per domain), a convenient web interface to manage your domains, an optional privacy facility where your domain name is registered in the name of a proxy company, etc. They offer .com, .net, .org, .biz, .info, .us, .ca, .tv, .name, .cc, .de, .sr, .md, .co.uk, .us.com domains, etc. If you're transferring a domain here from other registrars, the price is even cheaper ($6.99 plus 20 cents). Both credit card and PayPal payments are accepted here.
Just days after Verisign launched the Site Finder Service, ICANN wrote a strongly worded letter ordering them to disable it. Verisign complied, but not without writing a strongly worded letter of their own, in the form of a lawsuit. Verisign argued that ICANN overstepped their bounds in trying to control their activities, and ICANN argued… that Verisign overstepped their bounds in performing those activities.
In order to register any domain, you must provide certain personal information that you may not wish to be publically searchable in the Whois database. Signing up for WhoisGuard is a great way to keep your registration data private. WhoisGuard acts as a "shield" for your searchable information, displaying the address, phone number, and email of the domain registrar (Namecheap, e.g.) instead of your own. Keep in mind that WhoisGuard is an optional security add-on that must be renewed separately when you renew your domain.
You should also avoid words that have more than one spelling if your visitors are likely to be confused and mistype the name. Alternately, you can buy both versions of the name and direct visitors from the one you like less to the preferred name. While you do want a short name (see below), don’t go for something so cryptic that people have a hard time remembering it. Word of mouth is a powerful marketing tool and you want to make it easy for people to tell their friends about your site.