A point that I feel is valid, is unlike most Modern books, where only #1 is the "key" book, The Walking Dead offers many.
#2 and #3 to me, are a little undervalued considering the amount of key characters in the comic and show that make their debuts in those issues.
I believe the runs of those 2 books were sub 5000.
Add #19, #27 #53, #61 (I do not believe this will hold as a genuine key, but whatever - for the moment it commands a premium) and #92.
Some may argue that #108 and #127 may also become keys in the future.
How many other modern comics can boast an array of key issues, where in those issues previously mentioned, a character plays a huge role in either the TV show, comic or in the case of #19 + #27 - both?
It's not just about #1 - it's about the evolution of the series and the importance of the characters both on-screen and off - and their debut issues as well.
FWIW - I believe TWD #1 will be a $1000 - $1250 book in 9.8 (add inflation per year ) for as long as comics are collected.
I think these are the halcyon days, and a fall will occur, but to suggest that TWD #1 will be a sub $1k book is wishful thinking.
The other keys will fall as they fade from the 'front and centre' of the show and comic (#27) but they will still command a premium, and be very much sought after.