I'm really fond of Megatokyo, an online manga drawn by Fred Gallager, which story begun almost seven years ago. It is still updated every two or three days, and the story keeps going on. Basically, it describes the troubles of two young men "lost" in Tokyo, without enough money to go back to the USA... very funny !
To date, he has already drawn more than 1000 pages. His work is really impressive, and, if you ever read it from the beginning, you will truly feel his improvements : the firsts comics are actually low-key, whereas the last ones are deeply elaborate.
Anyway, I tried to draw some of his comics, and here are the results :