Back when I was just 11 or 12 I picked up a Marvel G.I. Joe comic book.  I think it was issue 34.  I became friends with a another kid who had all of the G.I. Joe comics and I would read them whenever we hung out.  I started collecting G.I. Joe.  In the 8th grade a friend said since I like military and guns that I should check out the Punisher.  Needless to say he got me hooked and I now have every Punisher comic ever printed.  Just about every Punisher appearance in a comic and when I was married my wife got me a graded copy of Amazing Spider-Man #129 for our 5th Anniversary.  
I collected other comics throughout the years, Uncanny X-Men, X-Men, X-Force, Wolverine, Captain America, Deadpool, but I always come back to the Punisher.