That's a good question, but again, Barclay's teaching is that everybody -- including all who blatantly reject Jesus (Hitler, Osama bin Laden, etc.) -- go to heaven. It's a dangerous doctrine because ultimately it removes all accountability and all responsibility to seek God, repent of your sin, and live for Him (because in the end we'll all get there anyway!).
I'm not so much into big name Bible teachers, but the best modern-day one that I know of is John McArthur (from the little bit I've read/heard from him). When I've heard him teach, he simply expounded a chapter verse by verse, and it was very good. I think he's pretty conservative on the scriptures.
As for commentaries, the Believer's Bible Commentary is pretty good, by William McDonald. It's very practical (and conservative on the scriptures).
These "secondary sources" (commentaries, study aids) are fine, but don't forget to study your
primary source first -- the Bible.
RoboOp