Domains drop every day and are re-registered by the tens-of-thousands (At least!) - a domain dropping is not forever "off limits".
Of course it matters on whether or not the name could be confusingly similar to someone else's TM, registered or common law, and whether or not they cared enough to bother you for it.
A name need not be a "registered" TM or a "registered" Company Name in order to still be considered intellectual property.
For example, "Common Law" trademark rights.
I don't need to go on at length about this topic here, instead, take a few minutes to read the wikipedia article on trademarks (I've started pointing more and more people to Wikipedia, despite it having such a bad rap ).