First, how long does the battery last on the 15" MBP with a 5400rpm HDD in it? Second, is the 2.33 proc worth the price? Do I need 1 or 2 gigabytes of ram? I run these apps at all time: firefox, itunes, word, textedit, calendar, macirssi, terminal, preview I also use mathematica and handbrake. I am upgrading from a pb 12" 867mhz 768ram machine. I need this machine to last at least two years; with intel procs, who knows how long they'll be good for. Thanks.