Puzzled about Baptism

We had a baptism at church this morning!  And, as has happened more than once when my church has had a baptism (see, for example, my post here), I became confused about baptism!

Here are two items:

1.  The liturgy said: "We praise You that in baptism You give us Your Holy Spirit, who teaches us and leads us into all truth.  Pour out your Spirit upon us and upon this water from the Jordan River, that this font may be your womb of new birth."

So is water baptism necessary for a person to be born again, or to receive the Holy Spirit?  The liturgy seems to suggest that, unless I'm misreading it!

The thing is, my pastor appeared to be saying the opposite in his sermon.  No, he did not say "Water baptism is not what saves you," but he seemed to be sticking with a model of salvation that I have seen so often within evangelicalism: that a person can be saved just by calling on the name of the Lord, even if he or she does not go on to be baptized.  You hear stories about people in their hotel rooms picking up a Gideon's Bible, asking Jesus into their heart, and becoming born again.  I remember being in a campus evangelical group, and the evangelist was telling us that we can be saved simply by sitting in class one day and asking Jesus into our hearts.  And the pastor this morning told us a story about a woman who saw Billy Graham on TV, watched him because she was too lazy to change the channel, and became saved.  She placed her faith in Christ, and her life changed.

The way that it was for me, I said the sinner's prayer (if you will) years before I was actually baptized in water.  I don't think I'm the only person like this, for I know even evangelicals who have not been baptized, or who became baptized long after their born again experience.
 
But the New Testament seems to me to associate baptism with forgiveness of sins and spiritual rebirth.  I think of Mark 1:4, Acts 2:38 and 22:16, and Romans 6.  My impression is that many New Testament Christians did not radically separate the initial profession of faith from water baptism.  Rather, what we often see in the Book of Acts is that people decide to believe in Jesus, and then almost immediately thereafter they are baptized.  There wasn't a long span of time because the initial profession of faith and water baptism, in short.

2.  Why was Jesus baptized, when he was sinless?  To be honest, I've not yet encountered an answer to this question that entirely sits well with me.  The liturgy says that Jesus was anointed as the Messiah at his baptism, and, yes, there do seem to be places in the New Testament in which baptism was the time of Jesus' anointing for his ministry.  But baptism is also associated with forgiveness of sins.  Actually, it's strongly associated with forgiveness of sins.  Did Jesus' own baptism lack that significance?  Well, I guess it had to, if you want to accept the traditional Christian view that Jesus was sinless, but how could Jesus' baptism mean one thing, while other people's baptism meant something else entirely?