i'd consider that a success!!!!

 
Here is a stock card along side my block:

It sits at roughly 90°C load temps.  This is quite common from what I have read.  My block sits right next to it and idles in the 30's.  Then I got rid of the stock card and I got roughly 70°C on the block.  Somewhere around a 20°C drop in load temps from stock.
 
Here is my blocks actual test after allowing the room temp to equalize and It was running for about 2 hours:

After 2 hours of idle, I did the test and got load temps around 65°C  with idle temps in the high 20's. 
 
 
Here is the (awful) setup:


I had to yank my entire system apart to conduct this test.  The block in the picture is a 2-4-6 block.  A common machinist tool.
 
The waterblock was on its own loop with a simple swiftech triple rad, and coolermaster 120mm fans.  Not exactly the best fans or radiator, but having a 25°C drop in temps (45°F for those of us who don't do metric)  is practically a season change in temperature.
 
 
 
 
 

Here are the results from a minute long test after leaving the system off all night and turning it right on:

 
Max of 59°C.  Obviously that will creep up over time, but if you had better cooling then the rad and fans used in this test, and using something better then Arctic Silver Alumina as your thermal paste, then you might see better results.

Thanks! This was my second Video Card block.
Next slab of copper is on the machine.

very cool but in a tower case where the weight of it is on the card would not turn out so good, a block like that your going to need a support frame system for it and for your card/cards in the case to keep your gpu's pcb from warping.

Some pics of block 2
 
Here is the Interior machining:

The outside was rough bandsaw cut, but it just shows how fine the interior machining is.  The exterior is last to cut.
 
Here is the back after initial rough machining and a 1/2 13 Bolt sitting on top of where the GPU will be:

 
 

Before O-rings:

 
O-ring groove machined:

haha, $$$$$$$$$$$$ilver waterblocks. 

Using this:
 

Ya my water temps rise maybe .5 C after passing through the computer. ;)

ANother killer project nateman, real interesting to me. It's cool to see the finished product. 

You sir... have... Lots of hats :P

Insides of block 3 is cut and block 4 is currently being cut.  Because what else would I be doing on a saturday night? ;)

Very nice work,It seems you've thought of everything,nice.

Testing my phone uploading..

Edit:fail. For some reason the buttons for loading images dont show up. Just to click on a smiley.