Yes it is worth the few bucks to get Arctic Silver 5. I did a personal test on my overclocked D805 and even giving the cheaper brands a week to burn in, AS5 instantly proved to drop the temp by 3-5C under load. Since then it has gotten even 2C less on my flame throwing processor
I am using an Arctic Cooling Freezer 7 Pro and under 100% load (2 instances of Prime95 and 1 instance of SuperPI 32Mil) I top out at 49C with an ambient of 25C. With a "knock off" brand's thermal paste that came with a VGA cooler my friend bought, I was hitting 55C but ambient was 26C for that time period.
For $4.99 at the egg it is a solid investment, especially if you are overclocking and one 3 gram tube is good for quite a few applications. I use it on my NB/PWM/SB/2 GPU/CPU and still seems to have enough left for a few more applications.
One other thing I would recommend reading into would be the new
Zalman thermal paste. I have read a few reviews claiming it is even better than AS5 but I cannot fully recommend due to my lack of experience with it. I can only recommend you do a quick 10 minutes of research if you are interested. It is $10 but it is easy to apply from what I have read. It is brushed on with an included brush and, no offence, you sound like it may be your first application of paste, so any help you can get is good
(You called yourself a noob first, so don't flame! We all start somewhere)