Have you read
The Other Side of Calvinism? I ask because I used to be a hard-line Calvinist (believed Unconditional Election, Irresistable Grace, etc) and so I understand the power of that "system" of theology. It took me a long time to start questioning it, but finally I got tired of blowing off verses like these:
Revelation 22:17 And the Spirit and the bride say, Come. And let him that heareth say, Come. And let him that is athirst come. And whosoever will, let him take the water of life freely.
I finally got tired of treating this verse (and others like it spoken by our Lord) as disingenuous -- if Christ knows we can't
freely come of our will then why does he make the offer?
Anyway, I decided to read the book
The Other Side of Calvinism and finally I realized the system of Calvinism is made by man, not from the Bible. Vance's discourse on Ephesians ch. 1 essentially answered it all for me, and the entire book helped me have a better understanding of God's grace and salvation.
It's my experience that no amount of debating will change minds on this topic. For me, it was a matter of study, which is why I wonder if you've read the book, and suggest you check it out if you haven't.
Many of God's best servants were/are Calvinists (Spurgeon comes to mind), but I think they are so in
spite of their systematic theology, and should endeavour for a greater knowledge of God's grace.