Not if its a strange combination that means nothing at all.
A new 3 or 4 letter domain name is nowhere near one that has tons of traffic and popularity.
It makes perfect sense that 3 letters are valuable. 1. they're rare, anything rare is always expensive. There are less combinations in three letters than anything over it. And 2. they're short, easy to type and easy to remember. That means whoever owns one will probably have a better return rate of views, etc.
Hah the only two letter domain I visit is ae.com, it's for the American Eagle Outfitters website. I love how simple it is. :3 I guess companies can really benefit from nice and short domain names since it's easier to remeber and easier to type. I wouldn't want to get myself a 2 letter domain unless to sell for money... I like words in my domain. :x