My favorite is definitely Cobalion. Its design speaks to me more than any of the other Swords of Justice, and its cry makes it sound like a badass in my opinion. I also really like its Steel/Fighting typing (even though it shares it with Lucario, which frankly, doesn't look like a Steel-type at all).
Official Shadow Crawdaunt of the Pokemon X/Y Boards and Team Miror Infinity "Just because I want absolute power, I'm the bad guy!"
Well...Cobalion had more story in PRB, but Terrakion is an absolute beast for the postgame there...Well, I'm tied on them I'd say, and the last time this came up I went for Terrakion so I'll go with Cobalion this time.
King of Hearts of the RI shuffle alliance Current form: Trace, a self proclaimed mad scientist.