Hi all, I have a 5.5G 30GB iPod and love it. I've been ripping music in MP3 at 192kbps. I use MP3 because it makes it easier for me to share music with people who don't own iPods, and I prefer 192kbps because I like the sound quality. But, lately, I've been wondering something. A lot of the music I listen (jazz and classical) consists of longer tracks, and so in some cases individual tracks are 12, 15, 18 MB in size. How do you think this will affect the battery life? Would I get more hours of battery life if I used the AAC format at a lower bitrate? I've read that the 30GB iPod has about 32MB of RAM, and so some people recommend not playing large files much if your goal is to maximize battery life. But I don't know how much 32MB of RAM really allows for, how much of the RAM is used by the firmware just to run the iPod, how many songs the iPod will store in RAM, etc. I haven't had time to run any serious file format/battery life tests, so I thought I'd post this message just to see what other people's experience might be. If it helps any, I've realized the following: 1) I'm willing to give up the MP3 format if I it means more battery life. 2) In running sound quality tests, I found that AAC at 160 kbps sounds very good to my ears. I'm not crazy about 128 AAC, though (but 128 AAC would create much smaller files). 3) I probably save about 1-2MB of space and up to 3MB of space for larger files for each song ripped at 160 AAC. But I'm wondering if that really makes a difference when it comes to the way the iPod uses RAM and how much it accesses the hard drive. Any thoughts?