I seem to remember a MtGox historical data CSV download somewhere, but can't seem to find it now... looking for, say, the price at the close of every day, or something like that. I don't need every trade, just trying to figure out a price I can use for each day that's mostly accurate.
If you click "Load raw data" on BitcoinCharts (below the chart) you can get an HTML table with the prices. Enter a date range and use "daily" granularity, for example:
- http://bitcoincharts.com/charts/mtgoxUSD
One a month (for a month-end summary) I update this:
- https://docs.google.com/spreadsheet/ccc?key=0AmcTCtjBoRWUdHJuUE1mUkFxa3A0eHBDQkxZLVVFZmc
And JSON version from blockchain.info
- http://blockchain.info/charts/market-price?timespan=all&format=json