Yea, I dont think there can be any absolute in most situations. It will always be dependent on the dynamics, stakes, players, blind level (I am speaking strictly tourney play here) etc.
No matter what you do - other than fold - you always want to consider how the table is going to react. Sometimes a limp can be OK. But it will "depend". Many times it will be wrong. Limping just cause you are afraid of folds to your raise is a bad reason to limp. On that type of table, you really should raise. As stated above, on a table where you are fairly certain your limp will be punished by an aggressive player, that is a different story.
There are many things to consider, but a raise is never wrong if you dont have any info on the table.