The Trinity: Belief Essential for Salvation?

Here's a question for you -

Can someone who is decidedly non-trinitarian (i.e., one who claims there is no Trinity - no Father, Son and Holy Spirit - but only Jesus) be a Christian? How essential for true, effectual salvation is belief in the Trinity?

Note that I'm not asking whether a correct understanding of the doctrine of the Trinity is essential for salvation (I doubt the thief on the cross had time to formulate his doctrine of the Trinity prior to Christ's telling him that "today you will be with me in Paradise" [Luke 23:43]).

Love to hear your answer or thoughts on this.

"All non-Trinitarian formulations of the Christian message are by biblical standards inadequate and indeed fundamentally false, and will naturally tend to pull Christian lives out of shape." Excerpt from J.I. Packer's Concise Theology (Tyndale House 2001)

More on the Trinity from Monergism.

Man's Chief End: Glorify God & Enjoy Him Forever

How are we doing in fulfilling and living our primary purpose? The chief end to which God has called us?

Q: What is the chief end of man (i.e., man's primary purpose)?
A: Man's chief end is to glorify God, and to enjoy him forever.
(I Cor. 10:31; Rom. 11:36; Ps. 73:24-26; Jn. 17:22, 24)

A great treatment on this is Thomas Watson's Man's Chief End, in his work A Body of Divinity (Banner Of Truth, 1984).

See also Thomas Boston's Of Man's Chief End and Happiness.

From the Valley of Vision (Banner of Truth, 1988)

Our Highest Blessedness: Knowing Him!

"If God is the Supreme good then our highest blessedness on earth must lie in knowing Him as perfectly as possible."
(A.W. Tozer, That Incredible Christian,WingSpread Publ., p. 65)

I'd say we need more than a "let's just love Jesus" mentality and theology.

You need to know the Jesus, the God, whom you love - Who He is, and who you are to Him based on the finished work of Jesus Christ.