Hi David,
Setting up eNewsletters is something I do a lot and I’ve used just about every service out there. Personally, I recommend iContact. It's the least expensive and has all the bells and whistles.
I used to use 1ShoppingCart. If you need a shopping cart and are trying to sell info products, they’re about the best thing for you but they're kind of expensive, hard to use and their deliverability rate isn't very good.
Constant Contact is pretty good but they start at $20 month whereas iContact starts at $10. Constant Contact has a newbie friendly user interface but they make it pretty hard to import your own HTML code. Plus, I don’t think they do auto responders.
I've used AWeber too but they require you to use double opt in which will reduce your sign up rate by about 25%. Plus their reporting is terrible and when I asked them about it, they blew me off. (It's not possible to have over a 100% open rate no matter how great your newsletter is.)
iContact enables you to do auto responders (which 1Shopping Cart and AWeber do too). It's also got a survey feature and you can archive your newsletter in their public community which has an RSS feed and could be a good way to easily get more subscribers.
Hope that helps,
Elge