...but I am curious. I'm positive that the Straw-hats are going to face off with the Blackbeard pirates eventually.
This is how I think the fights will go.
Luffy vs. Blackbeard.
Possible, it will be the first time Luffy will fight for revenge. Frankly, I'm terrified of the possible outcomes of this battle. I see two possibilities. One is that Luffy uses his Haki, and prevents Blackbeard from using his Devil-fruit power, a fight I see him winning. The other possibility is that Luffy will lose this fight, and die.
Zoro vs. Shiryuu.
For some reason I think that it's possible that Shiryuu will fight and/or kill Mihawk, thus taking the title of the world's strongest swordsman, which makes their battle inevitable.
Nami vs. Lafitte, OR Nami vs. Catarina Devon.
Lafitte is the Blackbeard pirate's navigator, BUT Nami has, up till now, mostly fought women. So right now, it's a toss-up.
Usopp vs. Van Auger.
What? Don't look at me like that, it's a perfectly logical conclusion. This looks like it's going to be a long-range battle. Usopp's probably not as strong, or as good of a sniper as Van Auger, but Auger doesn't strike me as being hugely imaginative, so hopefully that'll help Usopp overcome him.
Sanji vs. Jesus Burgess.
Neither of them seem to use weapons, and process of elimination. Maybe Sanji will bust out some of the Okama Kenpo he learned on Kambakka,
Chopper vs. Doc Q&Stronger.
Chopper, will, I assume, challenge Doc Q for reasons similiar to why he challenged Hogback.
Robin vs. Catarina Devon.
The reason I think Robin will fight Catarina Devon is this; Oda says Nami is the second-weakest in the entire crew. Robin, terms of strength, ranks much higher. Devon is apparently one of the strongest people on Level Six of Impel down, so in my mind, it makes more sense for Robin to fight her.
Unfortunately, we haven't got enough information about the rest of Blackbeard's crew for me to speculate on who Franky, Brook, and the mysterious tenth Straw-hat will fight.
Questions? Comments? Theories? I'd love to hear what everyone else thinks.