building waterblock

IM building a waterblock using my school's milling machine. I have access to everything from .5 drillbits on down.....so i am pretty flexible with what i can make....The milling machine uses WPLM CNC milling code and can be made in Autodesk Inventor 4 or 5. I am in the process of designing what interior designs / cuts i will be making. What is the most efficient design so far?...it is accurate to the nearest thousandth of an inch so it will look fairly good when done. Whould i go for a heatsink idea with many pins or more of a maze look?

Any input is greatly appreciated thanks.

few around here would attempt to tell you the most efficient design, anyone who would attempt to tell you what the most efficient design IS, would be kidding everyone - the most popular and highly regarded block is probably Cathar's white water, although there are a lot of blocks being produced, similar and different, that look like they could be good prospects. i think some of the pin fin blocks around here recently look real interesting, and with that equipment you could really make a nice one, but i havent seen how they perform.