I have been re-reading the Genshiken manga for the last couple of days and it is still as good as the first time I read it a year ago.
For those that don't know the story, Genshiken is a club made up of otaku that were excluded from the anime and manga club. Pretty much the manga is following the life of these otaku for a span of 4 years.
The character development is great because you see the characters grow up and mature over time. This manga does have fan service but not of the bouncing boobs kind. The type of fan service I'm talking about is references to different manga, anime, video games, and other stuff that is related to the otaku lifestyle. This manga is funny because of the jokes and references that the character bring up. The creator maintained a strong sense of realism that is scary, which in my opinion this manga is the best example of a slice-of-life manga. If you are not knowledgeable of the otaku lifestyle and you have not seen a vast amount of anime, you will not get the jokes and situations. I recommend this manga to all anime fans and otaku because this will be the greatest manga you will read in a long time.