i wouldnt call aweber rolls royce by any means there are a ton of mailers out, but for that quantity a place like aweber (or get response which is better) is cost prohibitive once you have more than 50-100k better to buy software (plenty out there) for a couple hundred bucks and use your own server(s)
Giving you the benefit of the doubt on how you acquired the email address, and that you have received permission from all of them to receive offers from you, I'd say you are still likely to have a hard time making sales with that list. It seems unlikely that a list that large can be targeted to any particular niche. It is hard enough to persuade people who have demonstrated a strong interest in a particular niche to buy products which are highly targeted to it. Sending emails to people which pitch products and services they have no interest in will not work.
I personally use Interspire to send emails.I send Bulk emails through Bulk Sender PRO. Hope it helps Simu