Shinichi/Conan has made it clear that he will never kill or allow someone to die.
Therefore, I believe he will have some sort of action-filled showdown, including a possible amassing of time-tested gadgets or simply reliance on back-up and minor characters. I'm hoping that Conan is the one to take Gin down, but it could very possibly be Akai who puts him away, since he called him his rival before his "death." I feel that as Bourbon's identity has remained a secret so much longer than any other organzation member besides Anokata, the end will near when that character is discovered to be a member, and either they will be an informant to Conan or somehow lead him on the right track, intentionally or not. Ran is definitely going to be told who Conan is, because once it's all over, it would be wrong of Shinichi to keep everything a secret and make her worry more. I assume all the side stories will wrap up afterward, so a lot of police and friends will probably be involved in the final showdown, if only to exhibit their usefulness, strength, and ties to the main story. However it happens, this will be a greater match than that at Reichenbach falls. :]