I don't know what you mean by closed-screw vs. open screw, and I've seen most kinds of banana plugs. I like to get the kind with plastic insulation around everything but the tip, makes for easier color identification and less chance you can accidentally short them together. The best I have seen are from Solen. They have a nice long insulator and
two set screws to hold the wire. They fit nice and tightly in any jack I've tried. The length may be an issue for some people. They're cheap, too. But, I don't know how it is ordering from Canada these days. They have a $25 minimum order, plus some miscellaneous customs fees if you're outside Canada. Their prices tend to make it seriously worthwhile though, if you're ordering a lot of stuff.
http://www.solen.ca/pub/cms_nf_catal...2=2&niveau3=43