Personal Reasons: Gmail starts sucking? Change email hosts, and all is mostly well with little to no interruption to your email service. Also, they can be good for personal branding.
Professional Reasons: A billboard, an ad, a business card. It looks foolish when a company is @gmail.com, for example. There are security reasons as well.
I use google apps for my personal email. If Google were to drop IMAP support or enforce terms of service that were unacceptable, I would have the option of easily pointing my MX records to another email host. If I was on @gmail.com, I would have a difficult time switching. For me, <$10/yr is more than worth it.
rentacar.com will get a free ranking boost on 'rent cars' that 'shertz.com' will not.
http://www.seomoz.org/blog/are-exact-match-domains-in-declin...
http://searchengineland.com/low-quality-exact-match-domains-...
I think it's still of value to have a good domain name, in the end there will be a big subset of users who will use it to reach your website. If you're running a webshop on the domain this could be damaging if they land on one of you competitors and get the product they want with them.
Unfortunately, there are still people holding onto things they bought 15 years ago, squatting them because they think they're worth millions. (Screw you, Barry.)
E.g. I can't get the .com or .co.uk I want but I don't mind much as I can get the .me or .us that I want.
Meanwhile, I know other people selling many many domains for a couple of hundred per domain who have made hundreds of thousands in profit.
So yes... domains are worth anything, but the value is generally determined by the buyer, and big domain sales like those that occurred in the early 2000's are becoming rarer.
* Employed individuals, probably not.
* Self employed individuals, yep.
* Businesses, yes but it's mostly subjective, interpretational, perceived importance.
And remember, there are always exceptions to every rule. :)
Names frame a discussion of a product or service. It's the difference between calling something a) a cancer stick b) a cigarette or c ) a certain genus of plant, rolled into a cylinder so that it can be ignited from a chemically powered heat source.
In regards to domain names, domain names are inexpensive because people have realized that humans imagination is so great that we don't need productDescriptor.com anymore. We can use domain hacks, or come up with a different name. Often not having pizza.com available to us prompts better discussion of what our service truly offers, and results in a better product.
If domain names were worthless, than I'd direct everyone to simply type 192.168.1.1 (obviously local subnet) in their web-browsers to reach my site.
But point on names well taken.
I'll admit to collecting domain names simply because they sound cool and I worry other people will snatch them up.
Have a few with vague ideas behind them that might never come to fruition.