best product to use to blowdry hair?

It really depends upon your desired style and your hair`s natural texture and condition. My friend and I have very similar hair (wavy, dry and thick) but we have completely different objectives when it comes to heat styling. She likes the bedhead look, and since her hair is short it looks great on her. That requires using gel at the roots for lift and pomade on the ends while drying. I, however, have shoulder-length hair that I dry stick straight. I can usually achieve my frizz-free goal with gel and silicone spray for shine and smoothness. I really like European Slick Melting Gel by Tresemme for keeping my hair straight and smooth, even in the highest humidity. For the spray I use a generic beauty supply brand with the same ingredients of those in the salon.

I`ve been blowing my curly hair straight for years.
I`ve experimented with all types of straightening balms, creams, sprays!
I think each person has to find their own combination of what works best.
What seems to work for me is a spray on leave in volumizer/conditioner, with a small amount of shine serum. After drying my hair, I apply a bit more shine serum and I`m done. I have been using Biosilk serum for years. Expensive, yes, but a little goes a long way, a bottle can last me more than a year! As far as the leave in conditioner spray, I use Matrix Amplify, but I think any kind will do.
Every time I have ever used a product designed to help temporarily straighten my hair, my hair has looked dry, dull, and my blowout doesn`t last as long. Almost all of these products contain alcohol, which is probably the culprit. Adding the leave in conditioner to your hair before blowdrying not only helps it look smoother and shinier, but it keeps it healthy in the long run.