If you want a biblically based Christian point of view on what's allowed and what isn't, here it is:

Following Christ isn't a matter of following rules except for two very general ones --

1) Love God.
2) Love your fellow human beings.

Those two Jesus specifically gave as summing up all the commandments.

Matthew 22:36-40 (NKJV)

36 “Teacher, which is the great commandment in the law?”
37 Jesus said to him, “ ‘You shall love the LORD your God with all your heart, with all your soul, and with all your mind.’ 38 This is the first and great commandment. 39 And the second is like it: ‘You shall love your neighbor as yourself.’ 40 On these two commandments hang all the Law and the Prophets.”

But why isn't it a rules-based thing? Read Galatians, and let Paul explain it. It's a very short book and not a hard read at all... though if you're used to legalism it may give you a headache.