I love it when guys grow their hair out. My husband tried but he gave up mid-way... if he would have just gone a few more months he would have gone past the awkward stage. It's a very hard thing to do, I think, for men to grow their hair out. There are so many stereotypes and expectations and judgements being passed around. Good for you!
My aunt did the Japanese hair straightening thing and it was pretty amazing. Too expensive for me to ever try, but her hair looked great until it began growing out. Then she had major roots that looked extra frizzy in comparison to the unnaturally straight treated section of hair. But while it lasted, it looked really super straight, sleek, and really pretty. I guess if you have the time and the money you could just go every other week or so (depending on how fast your hair grows) to keep getting treatments.
I have heard good things about the CHI flat irons, too. I personally don't have the time to mess around with flat irons, though. They can take a long time when you have thick hair.
I have very thick, very long (almost past my waist now), somewhat wavy hair. If I let my hair dry naturally, it stays wavy, but if I comb it straight right out of the shower (with a thick-toothed comb) and blow dry it, it stays mostly straight except towards the ends.
I use Matrix brand Biolage shampoo and conditioner. I really love this brand as it keeps my hair soft and silky, and I don't have "the frizzies" like I used to get with other brands. Another brand I like sometimes is Pantene... but if I use that for too long it seems like my hair gets greasy. So I sometimes switch back and forth between Pantene (which costs less) and Biolage (which works much better but costs more...). I've had people say that the greasy thing happens when you use too much of a product or don't rinse properly. But I'm pretty careful and aware of both of those things... so I think it's just the way Pantene works with me.
Something that really helps keep my hair really straight and shiny, for those days when I have time to care about it
, is a product also by Matrix called "Instacare solutionist". It's a spray, leave-in treatment. After my hair air-dries a bit (after being combed), I spray this in, then blow dry straight. Your hair has to be damp for this to work - not wet, and not dry. If you spray it in while it's wet, it won't soak in and doesn't work. If you spray it in while it's dry, it gets all goopy and greasy and funky. You have to towel dry, and then air dry your hair just a bit... comb it out a bit... then when it's at the half-way point in drying... spray this in (not too much) and then dry with a blow dryer. Sometimes I even spray the product on my hands and work it in that way.
I love my hair dryer. I just bought a new one recently because my old cheapie one that I bought at Target three years ago died. I spent a little too much on my hair dryer, probably, but it's the best one I've ever had! It's the T3 Evolution. I honestly don't understand how it works... but it dries your hair with this new sort of technology involving ions or something and your hair isn't frizzy after you blow dry it, it's soft and smooth. I wish I had bought one of these years ago.
Best hairbrush? Mason Pearson!! It'll last forever, and you'll use it everyday, so don't let the price bother you so much. We're not talking Target/Walmart/cheap quality plasticy brushes here. They are really good brushes especially for long hair. It's a classic!
I think wavy/curly hair can look really good on guys. Perhaps instead of trying to make your hair do something it doesn't do naturally... go to a hair salon and have a stylist help you find products that will enhance what you have naturally. I know Matrix also makes a spray-in type conditioner that works with curly hair. You wash, air dry, spray this in, and then air dry or blow dry. It keeps the frizz under control and adds shine. I think that would look really nice pulled back into a ponytail.
Anyway - good luck! Long hair just takes a little getting used to... forming new habits... I cut all my hair off a few times and it took a long time getting used to not having long hair. I even shaved my head once! It was a great experience, but I'll never do that again!