Is that "case" a case or a spider. I cant tell. Must be a case because a spider has 8 legs.... Sorry i dont know much about micro ATX builds, but i think for the budget i would go for a Phenom x4 955 Black
For an M-atx build with that budget you can go pretty all out. The only thing differen't about m- atx builds is that your motherboard is going to be more limited. But they are getting better and better. also with smaller cases heat will be a problem, as will fitting everything.
If your going water cooling, get a case with a good spot for rad(s). Make sure to get a modular PSU.
The first two links don't work. Those other casses are mid tower cases they are bigger and fit full atx boards (as well as m-atx, and some cases ,no pun intended, e-atx). Though theses cases will work for you, they will not take advantage of the smallness of your m-atx mobo. If you are looking at mid tower atx casses then their are so many that would match up with those two you chose.
(I'm not trying to be insulting but just so we're clear m-atx stands for micro-atx not mid-atx like the mid tower atx cases)
As for graphics go with a 5870 so you can crossfire it down the road.
I'm having a hard time choosing a case incase you couldn't tell. Do you have any recommendations for a case that will fit the h50 (120mm fan/watercooling) that is small enough to take to a LAN event without feeling like I'm lugging a full tower?
If your just going to be using an h50 as your only water cooling than many cases will fit your needs. If your planning on using it for LAN get a nice, stylish, small, light, m-atx case. not a mid tower. (but thats just me, i have a full tower, but really like the idea of a small box pc)