For pvp you have to run 120, because most spells are a direct check vs resist and most spell casters are 120.
For pvm 100 works well, but the biggest thing is the poisons which 90% of the time is countered threw forms or consumables. I don't reallly see a reason to use resist in pvm other then to counter bloodoath and/or you do a lot of semidar spawns.