Hello All,
On the acronym side of domaining, I'd define a 2 or 3 letter premium domain as one composed of only these letters:
a, b, c, d, e, f, g, h, i, l, m, n, o, p, r, s, t
Then again, with the prices that any pure 2 or 3 letter .com are going for, almost any letter combos (top letters or otherwise) seems to constitute a "premium" designation.
I do like the post above by WhoDatDog. Premium domains are really those that are of unquestioned and strong value. Any domain that gets regular offers via whois lookup emails would certainly point to a quality name.
zesty