I opened up an ING account initially to earn a free $25 credit and the opportunity to earn more for referrals. INGdirect.com allows you to open up accounts which are managed completely online. You must link it to a more traditional brick-and-mortar bank account for funding.
I love doing everything online, so I found this website to be extremely user friendly and easy to understand. I feel comfortable with their level of security and the process of logging in. I find it easy to open new accounts and I take advantage of this to create sub-accounts with different purposes. I even opened up an ING Electric Orange Checking account which I use to pay my mortgage and a few other bills. The checking account even earns interest!
When I opened the account initially, the interest rate wasn't highest in the industry, but it was higher than standard. I just felt that the website was easy to use and access and that made me happy. There are no fees involved with the banking or bill-paying. The only downside, to me, is that it takes time to transfer money between the linked account and ING. In the long run, it is probably good because that means that you can't just instantly access the money on a whim, which helps with the goal of saving.