Bitcoin Charts seems to only offer graphs of up to 60 days.
Bitcoin Charts currently have charts of up to a year in length, as well as "all data" charts.
Example 360 days:
You can see further back in Bitcoin Charts http://bitcoincharts.com/charts/mtgoxUSD#vztgSzm1g10zm2g25
Has a chart containing:
- average daily BTC/USD prices starting from 2009
- annotated historical events
- optional logarithmic scale
this is a great site too, but i believe it only goes to 30 days this is a live graph though
TRy this chart , also look at litecoin, the next bitcoin, @ $3. now with $55 M in the market cap. http://coinmarketcap.com/