I have got 362 vols of manga.
I might be neglecting to count a few since some have had to live on other bookshelves due to a lack of space, but I believe I have 753.
Also, every Shonen Jump from the first issue in January 2003 to August 2008 and every Shojo Beat from the first issue in July 2005 to sometime in early 2008. Some random issues of Yen Plus, Animerica Extra, Hana to Yume, and a few monthly comic issues (from back in the early days of Mixx and Viz) hang around as well for a total of about 40 additional issues/magazines.
I used to be quite the manga addict, but haven't really splurged on too many volumes in recent years. I doubt I even bought 100 of that total in the last 5 years.