Google Finance - good graph feature, can quickly modify the time scale of the graph from intraday to multiple years. Would be nice if they included dividend-included returns
Morningstar - The Morningstar X-Ray is useful feature for slicing a portfolio (especially an broad index based portfolio) into asset allocation components - cash, bonds, US stock, non-US stock, other, not classified. It calculates weighted avg expense ratio. Especially equity stock components, which are broken down by geo regions like N America, Japan; industrial sector, stock type, & a 3X3 box for Valuation (Value/Core/Growth) X Size (Large/Medium/Small). For bonds & cash as a total group, it has a 3X3 box for Interest Sensitivity (Short, Intermediate, Long) X Credit Quality (High/Medium/Low).
Seeking Alpha - note has avg bid ask spreads & expense ratios clearly listed
Yahoo Finance - good for historical prices & dividends