I am relatively new to the mac world so I'm not too up to speed on how to compare them. Right now I have a 15" G4 700 Mhz iMac and a AMD XP 2800+ PC. I use my iMac for just about everything, only using the PC when i need a little more speed. I am considering getting a fully loaded 15" powerbook. How will it compare to what I have now? Will I notice a big differance between the powerbook and the iMac? I had considered a G5, but I would liek to have portability. Thank you for any advice/info you can give me.