btw, don't pay attention to those saying you just need a members script and nothing else. It simply isn't true, as I guess you already figured out. You need (to the very least)
a) a great backend: you need everything to be fast and easy
b) great automation: you need your content to be created and handled without issues
c) a great front end: your site should work great. But, more important: IT HAS TO SELL
d) a great membership script: this is what glues everything in a package
e) a great architecture: are you going to use 2 themes (one for members and one for guests?) are you going to use virtual members areas? real members areas? tube style? reality? a mix? will you have social features? will you interconnect all of them? if so, how? how are you going to handle content? how will you deliver it? how will you protect it? what about alternative devices?
This is just the tip of the iceberg of what you should ask for TO THE VERY LEAST. If someone tells you "get a plugin and you'll be set" ... well, I wouldn't be very confident. I mean, I did this for many years and I know it's simply impossible, whoever tells you a plugin replaces marketing, aesthetic and sales tools should show you where and how did they apply it first
