I tend to look at spoilers after I've discovered something for my own already and want to avoid stupid mistakes. For example, IMO it would be rather stupid if you have to find Trigun, use Angel Arm, and then have to start your game all over and find Trigun a second time in order to be able to properly use it.
Incidentally, the second or third time I found a nuke went something like that... "It can't possibly just kill everything including myself on the level. That would be silly and practically useless. Well, I have to find out what it does sometime and it seems common enough so..."