RobinK,
It does depend on the game being played. Hold'em or any flop game would treat the card as an exposed card and it would be exchanged by what would be the next burn card. The first or second card dealt off the top would be a misdeal as you stated. I will asume it is a tournament because the rules are different in cash games. For example; tournament stud will call for a misdeal any time one of the first two hole cards is exposed by the dealer. In a cash game, if the dealer accidentally exposed one of the first two down cards, the dealer would deal the door card down, to compensate. If a player drops a card off the table, or exposes a card, they must keep it. Stud is a little more complicated because the exposed card could cause conflict when it makes a player low (the bring-in) where they would not have been , if the error had not occurred.
I would like to comment on your statment; "The card dealt off the table is an exposed card, but does not cause a misdeal unless it is the 1st (small blind) or the 2nd (big blind) card dealt." I know that you understand this ruling, but I'd like to point out a little technicality that might make the rule more clear; in the event that there is a dead small blind, the first down card to the UTG player would be the second card dealt.