The Torah requires a Nazir to bring a sin offering, and the bold name Bible commentators argue about the reason. Ramban says the sacrifice is an atonement for the sin of returning to the world after the conclusion of the Nazerite term. His position is disputed by Rambam who, following Rabbi Eleazar Hakappar, says the Nazir sinned by becoming a Nazerite in the first place.
The basis of the disagreement, apparently, is this: Ramban admires the Nazarite for trying to improve himself spiritually by withdrawing from wine and other vanities, while Rambam sees this desire to separate from the world as a sign of weakness and the rejection of what the Torah permits as evidence of a spiritual shortcoming.
We don't have Nazerites in 2009, but we do have our religious ascetics. They don't grow their hair long, and abstain from wine; instead they crown their heads with hats and refuse to partake from any number of permitted foods and activities.
The culture compliments these modern Nazarites. They and their chumrahs are held up as examples for the rest of us to emulate, while those of us who prefer not to copy their clothing and abstentions are dismissed as "modern" "not really committed" or "lazy."
Certainly the 21st centruy Nazaerites have the support of the Ramban, and the many mashgichim who cite him. The point of this post is not to condemn their approach, but to defend the alternative. Because, isn't it possible to be a full Jew in good halachic standing without taking on the various food and clothing stingencies? And, following the Rambam, isn't this "ordinary orthodoxy" a legitimate l'chatchila approach, and not second best?
This man sins against his soul when he completes his nezirut – for now he is leaving his holiness and Divine service; it would have been more fitting to remain a nazir forever, all his day as a nazir and Holy to his God. Behold he requires atonement when he returns to be besmirched with worldly passions - Ramban Bamidbar 6:14
If man should argue, since envy, passion and pride are evil, .. then I shall divorce and separate myself utterly from them till I eat no meat nor drink wine, nor marry .. after the manner of the gentile priests .. this is also an evil path and it is forbidden to walk on it. One who walks in the path is called a sinner and needs atonement -Rambam: Deiot 3:1