well that depends on the company's idea of "launch" for instance txtr (see the news section) "launched" their ereader today but what they mean is they have officially begun taking orders which may ship around Dec 15th. To other companies launch means they are deliverable that day.
1. If you want to purchase from one store then Kindle if you want to buy from Amazon and if you want to buy from B&N then Nook, Que, Irex DR800. If you want to purchase from any of the many Independent ebook sellers then you have a much wider selection to choose from.
2. Most of the Library ebooks are distributed by
overdrive.com so just about any reader that supports epub and Adobe Digital editions will be fine
3. well i dont want to be redundant