A coolercore from
Dtek
A waterblock from
DangerDen Maze2 or 3
A pump that matches your system. The higher rated (more gph) pumps have been proven not to offer better cooling unless you are running long lines. (Such as you have your setup outside your box)
I'm using an AquaVia 1300 and it works good but it vibrates too much.
If I was going to do it all over again I would have just bought a complete kit from DangerDen
consisting of
Maze3 copper block with 1/2" fittings
Eheim 1048 pump
Sunon 120mm fan
4oz of water wetter
artic silver 3
7ft of 1/2" clearflex tubing
1 reservoir
10 hose clamps
and one T fitting and 1 Y fitting
Yes you can get all of these for a hair bit cheaper individually, but once you add in shipping and running all over the place, this is much easier and a solid set up with everything you need.
If you can afford it I would probably get the Koolance external system. Not the best in cooling, but an easy to use and good looking system.