My input is that I believe it makes the most sense to start at Set #1, Disc #1. I say this for continuity sake because this is where we have the introduction of the Barnabas character into the show.
For selfish reasons I would prefer to start at Set #8, Disc #3 because that is where I happen to be in my watching of the DVD's. This is June 1968 at the heart of the Adam, Dream Curse storyline which I did not like at all when they last aired on SciFi but which I am finding more bearable the second time around. I would have been eight when they originally aired and they did not seem familiar at all when I saw them on SciFi. I believe I began to watch the show in the Fall/Winter of '68.
Also, if we begin at Set #1 we can, if we so choose get into a discussion about the Barnabas character because the fact remains if his character had not caught on like it did there never would have been a Dr. Hoffman, Angelique, Quentin, Chris Jennings, etc. because the show would have been cancelled before any of those characters were introduced.
I know there are many out there who do not care for or like the Barnabas character but as most everyone knows his character saved the show. The show was on the brink of cancellation and Dan Curtis threw in a Vampire as a last ditch effort to save it and the ratings went through the roof and the rest is as they say............. history.
MB, I believe you need to start wherever you think is best because no matter where you start it's not going to please everyone for one reason or the other.
.......Just my two cents
Murph