best thing to upgrade

[900RR]

By external I think he meant something like:
Newegg.com - ZALMAN Reserator XT BK Black Reserator (Reservoir+Radiator+Water Pump) Water Cooling System - Retail
or
Newegg.com - KOOLANCE EX2-750BK Liquid Cooling System - Retail

But it would be better to buy the parts individually, for a custom kit.

those look better than the danger den kits, because they have ram and nb water blocks too, not just vga and cpu.
External reservoir seems like the only way to go too. being in a 5.25 bay is going to increase it's temps

Here's why I don't want to go to water cooling

Cons: Res. leaked after 13 months, ruined MB, RAM, 2-New 8800 Ultra, tuner card, sound card, and left one ugly mess. Paid over $6XX.XX and Ruin over $28XX.XX in other components.

 

[Poizen22]

i liked this one quite a bit Newegg.com - ZALMAN ZM – Reserator2 Fanless water cooling system - Retail

if your resavoir is outside the case it wont leek inside, thats also why i kinda like the idea of teh external water cooling.

 

[Nagasama]

the lines and blocks can still leak. and it only takes a drop in the wrong place. poof.