Japan: My two sources are Stuart's Puroresu Fan (which has recently transistioned into a NJPW/Osaka primary site) and Zach Arnold's Puroresu Power, which is the one that appears on A1. Dealings with Mr. Arnold have taught me that Zach is a little bit insane at times, but better him having to translate than you.
Most everything: You want to find KrisZ's posts - he does a translated newsbits/show results/show lineup thing on a few different boards, including DVDVR's and PuroresuFan's
Mexico: HAVE YOU SEEN THE LINK DOWN THERE IN THE SIG. Because mostly all it is translated stuff and repeats from KrisZ. LuchaWorld can drop a newsbit or two, but it's really more a very quiet message board.
MMA: Scott was just telling me that there's no place for good MMA discussion the other day, but I wasn't paying attention because I don't care about MMA BUT the website I hear get thrown around the most is MMAWeekly
Indy: I've completely fallen out of the loop here. I remember waaaay back in the day that Jess McGrath used do some good stuff on 1wrestling, but I haven't checked it out in forever.
If you haven't been to RD Reynolds site Wrestlecrap yet today, I would highly recommend it. Seems he's putting out a book chock full of stuff from his site and more. I for one can't wait and can't think of a better person to get this kind of deal.