I must respectfully disagree. "Cold" is not the linguistic successor to
"cool." When Donkey says, "That's cold" to Shrek, it is not a compliment.
The current correct word to demonstrate approbation (and my teen-age
children confirm this), is "sweet." NB - When spoken, it should be
pronounced "sweeeeet."
Steve is absolutely right. "That's cold" means "That's nasty, mean,
sneaky, cruel, or despicable." Moreover, at least in Syracuse, the
traditional "That's cool" is commonly expressed as either "That's hot"
or -- Surprise! -- "That's cool."