DangerDen has some good options.
The best option for "no-brainer" watercooling right now is the Caorsair Hydrocool 200: better performance than any kit I've seen. It is not an internal setup though: radiator and pump/res are external and connect to the waterblock.
Before you spend the money though, you might want to ask yourself a few questions:
Do I want to save money?
Am a good at modding cases?
Which do I want more: performance (cooler temps OR quieter pc) or ease?
IF your answers are Yes, Yes and Performance than don't buy ANY kit.
Plain and simple, no available kit can match the performance of a homebrewed water cooling system.
No home brew system can match the ease of a kit, especially one like Corsairs.
Up to you.
(I'd just hate to hear that you spent $300 for a kit someplace and then found out that you could get better temps with an SLK900
)