Otaku, you say?
Higurashi no Naku Koro Ni - I am a big fan of mystery genre and this particular work is a gem. Perfect plot, characters, BGMs (in visual novels)... Couple of years ago I have spent whole week in Shirakawa-go, real life Hinamizawa. The signature valley-view is really beautiful, especially in the autumn. (If the anime version of Umineko did justice to its visual novel source, it would share the top place.)
Bakemonogatari and sequels - one of the best series of recent years
Steins;Gate - mind-twisting, addictive. Sadly, during my walks in Akihabara, I didn't find the IBM
Read or Die - OK, travelling Japan, how could I miss staying in Jimbocho?
Cross Game - I have discovered this series quite recently, but I just love the characters.
Well, is there something missing? Perhaps not, because I am yet to see a single episode of DC, so no place in the chart yet. Manga is just perfect for me as of now, though I should be worried about overdosing risks (300+ chapters in last 2 weeks).