Minamisenju, though a relatively minor, mostly residential area, is lucky enough to have three train lines stopping at its station — JR’s Joban line, Tokyo Metro’s Hibiya line, and the Tsukuba Express.
JR basically connects you to the massive JR train network, the Metro connects you to all the small corners of Tokyo, while the Tsukuba Express connects to you, well, Tsukuba up north.
Joban line (since 1896), is my line of choice as it is generally cheaper than all the others. I can go to Tokyo/Otemachi station for only 160 yen compared to 190 yen if I use the Metro. I know it’s just 30 yen but that adds up if used every day.
When I need to go to Narita airport, Joban can take me straight to Nippori station, where I can switch to the Keisei Skyliner straight to Narita. Nippori station (together with Ueno station), also connects Joban to JR’s Yamanote line, which can basically take you to all the notable places in Tokyo.
Hibiya line (since 1961), was initially the reason I chose to live in Minamisenju. I used to work in Roppongi so I saw Hibiya line as my no-transfer connection to work. I have since moved workplace from Roppongi to Otemachi so that is no longer valid but I still use Hibiya line as an alternative to JR.
Tsukuba Express (since 2005) is the line I use the least. Although it connects me directly to Akihabara, it’s more expensive than Hibiya line (which does the same thing), and it’s Akihabara station is very deep under Akihabara. Every time it’s like a journey to the center of the earth. The trains, as well as the stations are very new though and maybe I should use it to travel up north, one of these days.