I originally opened my Roth IRA through my bank, but transferred to Vanguard after the first year, hoping to escape management fees. I'm quite happy with the range of investment options available (compared to my previous bank). Vanguard's in-house funds are also great for setting up automatic, monthly deposits without having to worry about transaction fees.

Much like Fidelity and some other IRA providers, Vanguard has some in-house, target retirement funds (e.g. 2045 or 2050), which dynamically change their allocations and risk-level as you approach retirement age (along the lines of "set it and forget it"). While none of the target retirement funds are likely to out-perform the choices of a seasoned investor, they're a great option for beginners.

Lastly, the web interface is top-notch compared to some others I've used (e.g. my bank and other employer-affiliated 401k plans).