Lenovo battery vs. generic battery - Charge length?

[natgab]

I have a R61 I bought on ebay. The battery it came with now gives me only a little over an 1 hour. It is an original Lenovo 6 cell battery. Need some help as to cost / battery time ratio is best deal. I saw some Lenovo 6 cell batteries on newegg http://tinyurl.com/mahr3kp for approx. $69 USD. I have also seen some generic 6 cell batteries on eBay http://tinyurl.com/genericbattery for approx $17 USD. The 9 cell batteries go for about $24 USD.

I bought a generic battery for my old X40, I got about 3hrs out of a generic 9 cell battery. What kind of battery life do you guys get on T61 / R61s?