Not as big as compared to their Ikebukuro store, but still has a lot of anime/manga stuffs. Avoid weekends because it gets super crowded. All official merchandise, so no doujins (unless they're official). Prepare lots of money (I don't remember if they take cards).
If you like erotic manga and books, and doujin, this is the place to go. Not very recommended for girls (unless you're into kinky stuffs targetd for guys). If you're looking for BL, they most likely won't have it. 95% books only.
Mentioned by someone else, but the staffs don't speak English.
This place is great for the family, especially if you love Ghibli! I wish it was bigger though since it was just a small two story high building (and I wanted to go on the cat bus!). Ghibi Museum is a beautifully made place for fans as well as non-fans to visit and admire their exhibits.
Honestly, I don't know why this place is listed in so many travel guides. It's not exactly "fun" especially compared to all the other shops around in the area. Despite it being located in a new and clean building, it's contents are definitely lacking (the store isn't really a store at all). They used to hold weekly events (like radio recordings opened for the public to see) but I don't think they have anything anymore?
You can't miss this shop because it's right next to the station. I must say, though, that this shop is probably targeted more for guys than for girls. Still worth going in and check out some things, though their selection isn't much
Prepare your wallet! If you love anime and manga, this is like Disneyland (without the attractions... just lots of shopping). They have almost everything imaginable! Some stuffs may be cheaper online, but if you just want to be overwhelmed with anime related goods, this is the place to go.
If you love anime, manga, and games, this is a must go when you visit Akihabara. The shop is quite easy to spot with their large green sign. They offer goods not only produced by themselves, but also goods by other companies. If you like Monster Hunter, this is a GREAT place to find their goods. They also offer a lot of collectibles for female anime fans as well as people who aren't so into anime. They even have a Ghibili corner! It feels like a small Akihabara all compact into one store. Even if you don't buy anything, it's still a nice place to go window shopping (especially since it's so much cleaner than the average anime store!). They also have a nifty point card system where you get discounts for buying things!