I agree with Domainator. The three character appraisals depends on multitude of factors:
(in the order of raising value,
#1 being least)
1. Uncommon letters (no z, q, k, x, y, j are that valuable ($3k -$5k) EXCEPT if they spell a word or acronym/abbrev, so a vowel in there may push the value)
2. Acronym search - do they represent a few organizations or companies that haven't TM'd their abbreviations? Any LLL.com that ends in O or A or G or C that don't have Z or X AND match a few organizations, groups, or committees and conferences and conventions - bingo, the domain jumps to a mid low five figure domain.
3. Do they spell a word you can pronounce and defines something on its own? Sweet --you're looking at a domain worth high five figures up to a million or more (depending on the work the domain spells).
This same theorem applies to .net and .org, and even the .biz, .us, and .info domains, but cut the value in half or by 70 % as listed for a .com.
Again, it's all dependent on how bad the buyer wants it.
All in all, any three character domain, whether it's mixed with numbers or all letters, is valuable in the long run, especially if those characters work together to create a decent and memorable brand.
My advice as an appraiser is to hang on to any three character domain name in the top three TLD's, no matter what their alphanumeric combos are. They will all be worth a lot more a year or two from now than they will right now. Don't sell them out for the $100 prices I'm seeing on these boards just because they have a "z" and a "8" and "q" in them and are a .org. That domain, (i don't know who owns it, i just pulled it out of the air, will be worth at least $1000 by 2008.
Why? Heavy trading in limited character domains, high brand value, and most of all -- -LIMITED POSSIBILITIES OF COMBINATIONS.
Johnn and Rico are both correct with the examples you set forth. LLL domains can vary from a few thousand to a few million I would imagine. There are many variables--TM issues, pronounceability, brandability, type-in traffic, like letters, and so forth.
There are few really good names in the availble pool of names being sold--their values are high, but for the run of the mill LLL's avaible on the resale market, especially those with "z", "u", "x" etc those are under 10k and closer to 3k-5k.
Lastly, another rule of thumb to go by...a domain is only worth what someone else will potentially pay for it, determining who, what, when and where that someone else is, is the key....
:uhoh: