My battery life was halved with Lion, even following a clean install of 10.7.2 on a MacBook Pro 13" 2010 Core2Duo model. The battery monitor reported 6 to 7 hours' remaining on a full charge, which seemed reasonable, but after around 3 - 4 the system shut down with minimal usage. I've since gone back to Snow Leopard and can easily finish a full day at the office without a charge. Although the IntelCPUPowerManagement extension was updated beginning with 10.7.1 I noted via iStat Menu that when idling the CPU voltage refused to drop below 0.925V. In Snow Leopard the CPU voltage when idling drops to 0.725V, which I assume has a significant impact on battery life.
There's a huge thread over at the Apple Support Forum (must be over 70 pages by now!) where many users reported having brought their systems in to see an Apple Genius only to be told that the new features in Lion simply require more power and it's the price we have to pay for them. For those of us with MacBooks suffering under poor batter life we have the choice between longevity and iCloud. iCloud was nice at the beginning...photo streaming from my iPhone 4 and bookmark synchronizing were fun, but when my iPhone started dying after only a few hours in standby mode I had to delete the iCloud account on it and shut down all but the most necessary notifications.