Can one sin be worse than another sin, or are all sins equal? Since all evil acts come down to disobedience against god, are all evil acts equivalent? Is no sin worse than any other sin? If one sin is worse than another sin does that imply that one act can be more disobedient than another act? Is sin and/or disobedience absolute or does it have degree?
There are two primary views of this.

There are different levels of sin
All sin is equal in God's eyes.

Unfortunately, they're both pretty sound beliefs.
All sins are not equal
There are many verses to back up this belief that all sins are not equal.  Here are some of them:
Matthew 12:31-32 (NIV)

31 And so I tell you, every kind of sin and slander can be forgiven, but blasphemy against the Spirit will not be forgiven. 32 Anyone who speaks a word against the Son of Man will be forgiven, but anyone who speaks against the Holy Spirit will not be forgiven, either in this age or in the age to come

1 Cor. 6:18 (NIV)

Flee from sexual immorality. All other sins a person commits are outside the body, but whoever sins sexually, sins against their own body.

John 19:11 (NIV)

Jesus answered, “You would have no power over me if it were not given to you from above. Therefore the one who handed me over to you is guilty of a greater sin.”

Matthew 7:3 (NIV)

“Why do you look at the speck of sawdust in your brother’s eye and pay no attention to the plank in your own eye?&quot;

All sins are equal
The idea that &quot;all sins are equal in God's eyes&quot; comes from the idea that any one sin will lead to death.  If we commit a single sin, we are as guilty (in God's eyes) as if we had committed the worst sin--regardless of which sin we committed.
It's based on the idea that God's holiness is so extreme, that even one transgression is greater than he can accept.  This idea is supported with two key verses
James 2:10 (NIV)

For whoever keeps the whole law and yet stumbles at just one point is guilty of breaking all of it.

Romans 3:23 (NIV)

for all have sinned and fall short of the glory of God

The argument goes, therefore, that if even the smallest sin prevents us from attaining the perfection that God calls us to seek, then that one single sin is as great as the worst sin.
Summary
We can reconcile these two seemingly opposing viewpoints: we can clearly see that some sins are greater than others, but that any sin will prevent us from going to heaven without the saving grace and sacrifice of Jesus.
Essentially, any one sin is sufficient to keep us from God, but all sins are not the same.