These are nice and sturdy and work great for the speaker side since they're elbowed. http://www.amazon.com/Hi-end-Copper-Degree-Speaker-Connector/dp/B00X9CWAE0?ie=UTF8&psc=1&redirect=true&ref_=oh_aui_search_detailpage
For straight on connection, these are as sturdy, but you will need RTV or locktite on the backshell threads to keep them from backing off. http://www.amazon.com/Sewell-Silverback-Banana-Speaker-Connector/dp/B0072KOHQ4?ie=UTF8&psc=1&redirect=true&ref_=oh_aui_search_detailpage