another vote for Vanguard. Also do yourself a favor and pick up a copy of John Bogle's common sense on Mutual Funds. Although much of it is very dry and technical, it is a great resource. I often re-read chapters when I start to think I need to "do something" with my investments. Then I remember I don't have any special knowledge or experience and I leave my funds alone. If I look at my parents, siblings or friends, I can say Jack Bogle's writings have changed my life.

All my mutual funds are Vanguard although none are Roth.