From OEM line-up Dell AIO (Asustek) will be the best OEM cooler. Overall best - there are better both air and AIO out there, that would cost half the price.    
Ordering an 8950. I'm hearing that the stock cooler with the non-K chips is insufficient and that the CPU runs hot and quickly throttles itself. I'm going to avoid that. So the alternative is to order the K variant ($100 extra) and get the 125W advanced cooler. But there is also the liquid cooled option for an addition $50 (so $150 total). I haven't been able to find any tests or read any analysis that discuss the different between the 125W advanced and the liquid cooler. Dell's marketing claims "The XPS Desktop with liquid cooling is cooler and quieter under load than the 125W thermal solution." But I haven't seen anyone independently confirm that. Hoping someone here has some experience or thoughts on which would be best.
XPS 8950 Cooling. Experiences/Recommendations?