Longspelledoutwords.com are always harder for the user, if they don't want to type in 30-40 characters then your traffic will suffer until your site is indexed and bookmarked so folks don't have to type it any longer, so a short domain is always better.
If Google was named, "findanythingonthewebwithGoogle.com" then less folks would use it.
I agree shorter domain names are easier for users to remember as well as less mistyping. I wasn't sure if the longer "key word" domain would lead to better search results. I guess there has been a lot of debate about that and I don't want it to turn in to that.
Do you feel a .com domain is better then a .net domain. I know I prefer a .com domain personally but with how big the web is now .com isn't so much the commonplace anymore. It does however make you wonder if you have a really cool .net domain how many people that may have visited your site typed in .com at the end instead.
I tend to register as many TLD addresses as is available and park them so they redirect to one.
And if someone may mistake one name for another, I would register both.
I think short is good. I also think having the topic of your site in the domain is very important.
My hobby site is 318ti.org. While most people here would not know what it is about, anyone with a BMW 318ti would.
And anyone searching for '318ti' would find it on the first page of their search engine page.
In this example the long domain is infinitely better than the short one. For a lot of reasons (unless you're starting a discussion site for Nazis).
I'm not sure where the prevailing wisdom in this thread is coming from, but in every study I've ever seen that relates to domains (yes, there are such things) I have never seen evidence that there is user resistance to long domains that make up a phrase or a name. In fact, people prefer them to short acronym domains, because they have to mentally translate the full product or company name to the acronym in order to type it (though that would not apply to a model number domain like 318ti.org).
There is a limit to how long a domain can be and still be useful, so you can't use a really long phrase. But there are millions of two word domains out there for the picking if you are even mildly creative. Or use three words. That's still not too long, and you'll have yourself a descriptive domain, which is better than a short meaningless or acronym domain.
Sure, a three or four letter word .com, .net or .org is a great thing. But don't let the quest for shortness saddle you with a bad domain.