hey, a comment back there got me thinking, does anyone around here feel that computers aren't really getting that much faster, its just that when you get a new one, its really fast, as many of you know. overtime they seem to get slower. that could be a mental thing where you just get used to the speed, but then i noticed that my 2002 iMac g4 that just got wiped clean was booting FASTER than my 3 month old macbook alu! it also opens apps (older ones, but still newer than the age of the hardware, the macbook is running stock) at around the same speed. were talking 700 mhz 256 kb VS 2000 mhz 3 mb processors not to mention all the other specs! i dunno, just a thought.
oh, and the imac listed in my tag is not the one im talkin about.
You just need to do a fresh install. This is more of a problem on Windows, (though it started getting better with Vista), but as you install stuff and uninstall stuff, your system gets a bit gunked up. Not to mention how full your harddrive is makes a difference, etc. Beyond that, the biggest thing is that the software tends to get more resource intensive.