I pulled out my little TIM case, which is totally a small metal lunchbox-type case, I have 3 different kinds in here. Zalman ZM-STG1, IC Diamond, and Tuniq TX-2.
 
The IC and the Tuniq are definitely a paste, nice and think but I honestly can't remember when I last used them...I want to say I used the IC when I upgraded my AIO CPU cooler last year?
 
I really liked the Zalman because it comes in pretty much a nail polish bottle, complete with brush. This made application and exact coverage a breeze. I know for a fact I used this on all the heat pipes on my mainboard and it lowered my NB/SB temps substantially.
 
Can't offer you much more than that. I know I used AS5 before as well. From what I remember reading all the well-known brands are fairly close in performance. If you are really serious about it there are plenty of reviews out there and you should consider lapping. The results I have seen from that have been more substantial than which TIM they used.

Still use Artic MX-4.

This is a good thread. Hopefully we will see some good recommendations. I'm still using MX4 as well. It works really well.

Phobya HeGrease Extreme Thermal Paste - 3.5g
After Years and Years of Artic Silver I switched to HeGrease and love it.
Great shelf life too which can be a concern with TIMS like IC Diamonds and others I've tried.
 

 
SOURCE SkinneeLabs
 

After using Artic Silver for years, switched to MX-4 the last time around.  Non Conductive is a big deal for me!

Sajin
Currently using NT-H1 on my H320. Here are my temps after 1 hour realbench stress test @ 4.4GHz on the cpu/3.8GHz on cache & 3400 on the ram.
66.5c averaged which is just under the allowed tcase for the 5960x. 

+1 on the Noctua NT-H1.  My tube is about 3 years old and hasn't dried up or anything.  It's also non-conductive, really good consistency for spreading, and doesn't need to dry/cure.  I think that for the most part there's only 1-2 degrees separating the best from the worst (not including liquid metal) the biggest factors come down to ease of use. 

 
This question is asked alot.   
 
 
http://forums.evga.com/search?searchid=1073136&phrase=best%20thermal%20paste&high=best%20thermal%20paste
 
 
 

I have had the best luck with Arctic Silver Ceramique. The worst stuff was EVGA Frostbite

 
http://www.amazon.com/2DY3379-Antec-Diamond-Thermal-Compound/dp/B005BKT028/ref=sr_1_2?s=electronics&ie=UTF8&qid=1457911232&sr=1-2&keywords=Antec+Nano+Diamond+Thermal+Compound+Formula+7

owcraftsman
I see no Tim being recommended here in this thread not represented in the roundup. Until I see a better more current lab controlled roundup It's still quit relevant to all concerned. 
Phobya_HeGrease_Extreme_Thermal_Paste
If I were to try anything new it would likely be Thermal Grizzly Kryonaut
seen here

This Thermal Grizzly Kryonaut seems promising - a quick search shows really good results on it.  It also comes with some applicator thing that looks pretty interesting https://www.youtube.com/watch?v=TRytGgmdeQM -  I think I am in for a tube!

bill1024

Cool GTX

bcavnaugh
Still use Artic MX-4.

+1
 
Artic MX-4, doesn't dry out or have to cure --- just plan works from day 1 to year 5+

Me too, seems to work good; it is non-conductive, that's always a plus. 

Me four works great and all the good points above!
 

WackyWRZ
Finally got in the Thermal Grizzly Kryonaut today, that stuff is a little hard to find and a bit pricey compared to the others!  First off its some thick stuff - I tried using the spreader thing it came with but that was a no go. While attempting to use their spreader I had difficulty getting it to stick to the IHS it would just peel off - almost like a peanut butter cookiedough consistency or what you'd scrape from a stock CPU cooler.  I abandoned that method and just went with a small rice grain spot in the middle.  
 
What I'm seeing are load temps a good 6+ degrees lower than my previous Noctua TIM.  The 4690K@4.6G is running about 58 degrees with either AIDA64 or Prime95 2.66 running small FFTs.  My 980ti running Valley Benchmark maxed out at 1440p is holding at 42 deg boosting to 1517MHz.  All tests were done around 21 degrees ambient room temp.
 
These are far from scientific tests but overall I'm happy with it.

Nice. Might pick some up for a tim swap. 

Scarlet-Tech
I am NOT impressed with the amount of force it requires to spread, or that it sticks to everything rather than spreading as easily and evenly as MX-4. I will test the cards tomorrow night, after rebending twice pipes to connect the cards into the loop, and try to post back. No promises though.

I'm glad to see someone else that had difficulty spreading...  I honestly thought I didn't clean the surface well enough and that's why it wasn't sticking.  
 
Before buying I had seen this video: https://www.youtube.com/watch?v=TRytGgmdeQM of it being spread/installed.  I can say that what he is using does NOT spread like what I have whatsoever.  His looks MUCH more like Hydronaut than Kryonaut.  I have a tube of both since I wasn't paying attention and mis-ordered the first time.   I've also read in the YT comments (after the fact) that putting the tube in hot water for 10 minutes or rolling in your hands to warm it up significantly changes the spreadability.  That said I'm happy with my temps so I'm not gonna mess with it (for now).  I've got another build coming up I will try warming it up on that one.

I wonder if putting the Kyronaut in the microwave would hurt the compound ? maybe in a cup of water then microwave
 

I was going to say , - I always use :
 
the coffee cup , 3/4 filled w/ water , microwave it for 2 mins.
then sit the TIM tube in that on the table for a minute
everything goes on smooth like butter