I own a handful of domain names, some for corporate purposes, and I also have a personal domain that I use for my personal email. This domain name is sort of a pun on my last name, and it's a made-up word. Combined with a tricky orthography (there is an 'L' next to a 'T' which, when written lower case can look like a sloppy 'H'), I'm always hesitant to give it out in any form other than electronic since it will almost assuredly be mistranscribed at some point.

When I selected the domain name way back in '99, I never considered the "confusability" factor of the name. I'd love to select a new domain to use for personal purposes that is easily understood in non-electronic contexts, but I've had trouble selecting one that meets all the necessary criteria. Here are my basic constraints:

• It must be easily understood when spoken, such as when given out over the phone.
• It must be easily understood when written, either in upper or lower case letters.
• It should be interesting enough to be memorable, but not goofy or unprofessional such that I would be embarrassed to write or speak it.
• It must be available!

These constraints imply a lot of things, based on my experience.  To be understood in a spoken context, the name must:

• Consist of dictionary words, preferably a small number - Non-dictionary words, especially cutesy ones that you find in a lot of domain names, almost always require a letter-by-letter spelling.  Negative bonus points for intentional slight mispellings of a common word (Flickr and other annoying Web 2.0 convention-followers, I'm looking at you).
• Avoid homophones - People will invariably use the wrong version.  You will be surprised how many homophones there are when you start trying to come up with names that avoid them.
• Avoid numbers - Unless you want to buy both mydomainone.com and mydomain1.com
• Avoid sounds that run together and create sound-alike words - For instance, you probably don't want to go with MicePace.com

To be understood in a written context, the name must:

• Avoid i, l unless in a totally unambiguous context - They will inevitably be transcribed alternately as each other, or as the number 1.
• Avoid o, unless in a totally unambiguous context - It will inevitably be transcribed as a zero.

Finally, the trickiest one: something that is memorable, but not embarrassing must:

• Use an odd combination of words, or be oddly related to the person or service using it.
• Use hard consonants or alliteration to create a strong sound
• Evoke a strong image in a person's mind.

So what domain names currently meet all these criteria?  One great example is amazon.com.  It consists of a dictionary word, does not have a homophone or other sound-alike element, has no numbers, uses 'o' in an unambiguous context, is oddly related to the product, and evokes a strong image.  Distancesoftware.com is not outstanding, as the ending 's' of Distance and the starting 's' of Software blend together in a spoken context, but overall I've been happy with it.  If you have other examples of either very good or very bad domain names from a confusability standpoint, please post in the comments.  I'll update when I select a new personal domain.