I used to buy one manga every two weeks or so, but since my interest in anime has diminished (there's a direct relationship between anime and manga interest I suppose, but it's not that way anymore) and also and the availability of popular manga titles on the internet has increased, my growth rate has fallen a LOT. But this is what I have as of now...I'm thinking of maybe getting back into it, though. I stopped watching anime alltogether (except for a few old favorites) but I still have interest in manga but I don't get around to reading it anymore.
(Organized by amount of volumes)
-Love Hina: 1-14 (
Complete)
-Chobits: 1-8 (
Complete)
-Genshiken: 1-8 (
Complete) (as far as I know, it's not continuing

)
-Battle Royale 1-11 (
Complete)
-Eyeshield 21: 1-9
-Great Teacher Onizuka: 1-5
-Full Metal Panic!: 1-5
-Dragonball: 1-5
-Mahoromatic: 1-4
-Angel Sanctuary: 1-3
-Yotsuba&!: 1-3
-Junk Force: 1 + 2 (couldn't find any after this)
I have one copy of the first volume in following titles (along with reasons I didn't buy the next one):
-Sailor Moon (my very first manga at 12...my dad almost didn't buy it for me because it was 10 bucks, good thing he did, though. I never bothered continuing, as my manga interest rekindled two years afterward)
-A.I Love You (Ken Akamatsu's story style hasn't changed at all, and it bored me to backtrack)
-Rurouni Kenshin (buying it in the first place was kind of ridiculous considering I had read the entire series at the bookstore before buying this)
This counts, I think. I have all of the issues ever released of Shojo Beat (which is about 30 issues)... which is the girl version of Shounen Jump. It's good stuff. I also have an Angel Sanctuary art book I received for X-mas last year.