Weirdly-- considering I first started watching it c.1999 and it's always been one of my favorites-- the last anime I finished was InuYasha. :D I'd seen all of it to a point, then fell away from anime for about a dozen years; and when I got back into watching it last year, I found out they'd finally finished the series. But I didn't want it to end, lol, so I watched it at a very sloooooow pace, not getting to the final episode until about four months ago!
Bakuman- All three seasons :)
Natsuyuki Rendezvous
Concrete Revolutio: Choujin Gensou - The Last Song
Natsume Yuujinchou Itsuka Yuki no Hi ni
Natsume Yuujinchou Nyanko-sensei to Hajimete no Otsukai
Mayoiga