Oooooh, a loaded question if ever there was one! Honestly, the best answer is you should try both. Hear us out...
PROS AND CONS OF KNITTING
Knitting is the one that gets all the traditional love. You are going to see knitting in movies and pop culture much more than crochet. Knit is going to be the look of most of the sweaters and blankets that you see in stores and magazines. Knitting straight up has more patterns available.
What's the downside? It is slow. It takes more time to knit than crochet an item, and for many it is harder to learn. Creating knit patterns is also quite linear and mathematical. It's generally an advanced skill to be able to make up a pattern on the fly - especially for garments that need to fit like hats, sweaters, gloves, and socks.
PROS AND CONS OF CROCHET
Crochet, for many, is more easily learned. And, even better, it's way faster than knitting! Twistedista Anny has a crochet baby hat down that she can whip out in about an hour whereas Twistedista Dawn's best time for a newborn knit hat is 3-4 hours. Crop top? Anny says it's 6-10 hours for crochet while a knitted version takes 24-48 hours.
Another perk of crochet? it is far easier to go rogue and make things up. Part of the reason that there aren't as many crochet patterns out there is that most experienced crocheters just start getting creative and trying things rather than worry about finding a pattern for exactly what they want.
Are there downsides to crochet? Well, yes, the first being that it generally takes more yarn - 50-100% more. The second is that gauge can be trickier to get in crochet which makes creating wearable garments that much harder to achieve. Finally, there are fewer patterns available for crochet, but still more than anyone could ever make in a lifetime.
SO WHY TRY BOTH?
Because you never know which you are going to like better without trying them both. People tend to gravitate towards one or the other so if you started with knitting but find yourself more frustrated than happy, give crochet a go! Ditto the opposite. And if you are lucky enough to not have a preference, then the world truly is your oyster!