You really can't read Roman's 5 and comfortably hold onto the idea that God limits his effectiveness or scope of actual salvation. Take a look at some of the articles below.
A brief description of some of the evidence to consider:
Professor Talbott's article on Exclusivism shows the logical/biblical inconsistancy of believing that God has somehow excluded, by either weakness or apathy, some from his plan for salvation.
The article on Atonement simply lays out, from the primary passages on the topic in the Bible, the case that there is no other Biblically consistant possibility for the scope of atonement other than ALL.
The booklet "Is Hell Eternal or will God's Plan Fail?" is an old work, published in 1931, on the topic. This has been an on-going discussion since the time of the early church.
History of Endless punishment is pretty self-explanatory isn't it?
Does Eternal Damnation Glorify God? Well, does it?