Akihabara should be explored, of course. The sights found on the back streets and along Chuo Dori are worth seeing, and there are several other stores to browse. But this is arguably the best place to shop in town for anime and manga goods.
Access is pretty easy from Akihabara Station. Just take the Electric Town exit and turn left out of the ticket gates; follow the road to the right and it's the second building on the left. You can see it as soon as you exit the station (see my first photo). The stores are open 10:00-20:00 (sometimes less); the Ginza Lion restaurant is open 11:30-20:00