Almost everyone goes through the stage of being interested in horror/mystery/suspense anime, but dude there's way more to it than that. If you want a nice little horror stuff, you're not gonna get it. Unless you believe gore=horror. There are no legit scary anime, only ones filled with blood, though I'd still recommend Tokyo Ghoul. Trust me though, the good anime are usually the long ass adventure/action ones, those are the time you wanna get immersed into. Sure it seems more appealing to be immersed in a more realistic and serious anime, but you're gonna have the most fun with anime like one piece or naruto. The vampire anime you were talking about might have been Hellsing, since the original one got canceled (manga wasn't complete). i personally can't stand it, i despise it but i guess it's just not my cup of tea.
If you're looking for a slightly shorter anime then I suggest Samurai Champloo. It was the second anime i watched and was definitely the reason i got into anime. It's samurai/action/adventure, and it's a good time.