I couldn't agree more with what Jekaterine said. The difference between 4 and 5 in a skill is pretty small, considering the time it takes to train that. For most everything you'd want to do (yes, this includes research, mining, marketing, mission running, ratting, PI, and pvp), 4 is plenty sufficient.
For pvp especially, you'll spend a lot of time either dying horribly or winning easily. Having skills at 5 instead of 4 would perhaps turn a very few of those losses into wins, but otherwise it's all down to personal tactics on your own part. Player skill trumps character skill in pvp.