Ryou Horikawa was born in 1958, Jan 2, and his hometown is Osaka. Just like the previous featured seiyuu, he also likes doing sport, according to ANN swimming and baseball. Apart from that I know nothing of him. My personal history with Horikawa has been rather short and uneventful, yet his roles made such a great impact on me I had to mention him here.
Probably the most famous among Horikawa's roles is Prince Vegeta, a main adversary and then an ally of the protagonist in "Dragon Ball Z", as well as one of my most beloved anime characters ever. Why did I mention about having known Horikawa so short, then? Because when I watched DBZ for the first time in 2001 and re-watched it in 2010, it was French language version. You know I really hate dubbing, but Polish TV broadcast only French version... which I found surprisingly good! (Even though I don't like French, on top of it!) Last autumn, I re-watched DBZ again, and that time it was finally original Japanese version - and I did it ONLY because I wanted to hear Horikawa's Vegeta :D And you know, the character became even more perfect with that voice ^^ (Ok, in 2013 I did see DBZ Movie Battle of Gods, and in Japanese version, but what is 1.5 hour long movie to really hear the character? So it doesn't count.)
What in the first place got me interested in Horikawa? Last spring I watched "Saint Seiya", where he portrayed my favourite character, Andromeda Shun. (Well, I had known the heroes roughly, and Shun had been my Number One for some 20 years before I actually watched the anime itself :P) I was pretty much perplexed by that fact: how come that sweet and effeminate boy could have the same voice as a personification of manliness and battle-crazy warrior prince??? I just couldn't grasp it. Yet, Horikawa managed perfectly well voice two so completely different characters, and he is simply admirable as Shun.
After such a positive experience, I decided to move on to another classic anime from 80/90's, and that was "Legend of the Galactic Heroes". I still wonder why it took me so long to watch that absolutely magnificent series. I watched it May-June and then re-watched it August-September. It's one of the definitely BEST anime ever, and it's no wonder since it's based on an actual novel (10 volumes per 500 pages), not manga. The story would make a great live-action film, too. Horikawa boldly played the main character, Reinhard von Lohengramm, a genius space fleet commander, extremely skilled strategist, who quickly rises in the military and political hierarchy in his wish to change the rotten system he'd grown up in. And I tell you this one thing: if you admire such characters as Light or L from "Death Note" or Lelouch from "Code Geass", you had better forget about them at once because Reinhard is on a completely different level. And, what's the most important thing, he isn't a psychopath. Reinhard is ambitious, proud, intelligent, and goal-oriented, but also in need of his important people and clearly aware of his own shortcomings. Horikawa played that role in a splendid yet natural way, creating a living man, not some icon. By the way, I strongly recommend LoGH to everyone, for it's a piece of very good anime.
There's only two more roles I heard Horikawa in: Takeshi Onimaru in "Kenyuu Densetsu Yaiba" and Karasu in "Yuu Yuu Hakusho". Onimaru is the main antagonist in said anime, at first a normal high school student who turns into demon lord xD I watched Yaiba in early 2000's, but didn't pay attention to seiyuu then; I re-watched the anime last autumn, without even looking at the cast list, and recognized Horikawa right away. Karasu is one of numerous antagonists in tournament (anime arc 2, if I remember correctly), and the only one I remembered after watching the anime :P I didn't even know it was Horikawa speaking, back in 2010.
I know I'd be happy to hear more of his roles, but I'm not sure whether it's going to happen. Well, I'm pretty sure that one day I'm going to re-watch DBZ and LoGH again... ^^