This is such a widely debated topic and a lot of it comes down to personal choice. I learned to cook in Japan when I lived there many moons ago. My teacher was a fantastic chef who ran an Okonomiyaki shop in the first level of my apartment building. I learned to wield and sharpen knives from him. (I would sharpen and clean the kitchen's knives in exchange for free meal and got pretty good at it.) There were basically only three knives the chefs / cooks would use and a Santoku was NOT one of them. There were three shapes they used:
1: Nikiri - Nakiri are double bevel knives designed specifically for working with vegetables. Nakiris are characterized by their flat profiles and squared off tips. This profile makes these knives ideal for push cutting and chopping but awkward for rock cutting. Nakiris are often ground thin to optimize performance and they benefit from a refined cutting edge.
2: Bannou - General purpose chef's knife double bevel edge shaped just like a western chefs knife, but with a little more upturn in the tip. This shape will tackle just about anything you slice through. I use this blade every time I cook.
3: Yanagi - Long thin single bevel blade designed for slicing in one drawing stroke. Perfect for making thin slices in fish, but works just as well in other meats.
From this experience I went to make my own knife set that I use to this day. As far as materials go, I could have spent a bundle on damascus, stainless, high carbon, titanium anodized blah blah... You know what I ended up with? (Because I'm poor) Plain Jane, run of the mill, no frills iron. My knives are cheap Bishoku Iron knives that run about $20 each. Why do I like them? They are the sharpest freaking knives I've EVER seen. (I've even compared them to Shun and Wusthof.) Out of the box, they are pretty sharp. A couple of strokes down the ceramic rod and they are dangerously sharp. A couple passes on the razor strop? OMG! The Nikiri split a huge Idaho russet end to end like it was going through butter.
There are some drawbacks to Iron knives though. Keep them dry, keep them clean. Even after your best efforts, the acids and natural chemicals in the foods create a patina on the blade that I find kinda cool looking. A quick pass with some fine grit wet sand paper will clean it right up. Then hit it with some cooking spray to keep it from oxidizing.
Other than that, my iron knives remain extremely sharp and keep their edge for about a week of everyday use.