macbook pro 17 (Late 2011) battery life seems short?

Hi all, I expected my new MacBook Pro 17 (late 2011 model) to have a better battery life than my old (early 2008) model because of newer technology and it has the built in batteries rather than the removable kind. But it appears to be worse ????

Just watching it running and downloading XCode (2G) with the displat at around 90% brightness, I looks like it's going to completely drain a 100% full battery in about 2-3 hours.

IS that right?

ciao

Derek