The list looks good so far; remember that you'll have to factor in the price of the O/S as well as the other components, the only thing I might consider changing is your choice for coolers. While the Corsair H50 is a really good (self-contained) water cooler; there are other options within this same field: Corsair's new H70 is supposed to be even better than the original H50, but comes with an upgraded price as well, and there's also CoolIt's Eco or Vantage CPU coolers
As for PC cases; this is totally a personal choice, but the thing to remember is that because this PC is going to be used for gaming (primarily) then the components are going to get real warm, be sure to get a case that has good airflow (and a window, in case you want to show off your creation). Companies that produce some great cases include Lian Li, Corsair, ThermalTake, NZXT, Antec, Cooler Master, Silverstone, Zalman (to name a few).
Link to Newegg.com (PC cases - Price: $100-$200 - No Power Supply - Best Rating-Mid Tower):
I'm building a gaming dedicated computer for under $1500. I know very little about computers, but I assembled this shopping list based on advice from friends, and I am hoping to get a critique on it before I put in the order on Newegg. Also i haven't picked a computer case yet if you have suggestions (under $200). Thank you much for any advice!
Intel Core i7-860
Radeon HD 6870
MSI P55-GD85 motherboard
Mushkin Enhanced Blackline 2GBx4
Antec TPQ-850 850w
WD1002FAEX 1TB 7200 RPM SATA 6.0Gb/s 3.5"
CORSAIR Cooling Hydro Series CWCH50-1 120mm