A lot of people here seem to think that complaining about a five to six second start time is just whining. I believe you're wrong -- it is a legitimate and valid complaint and here's why:
Most software can't run for very long. A lot of high-end software can be /very/ unstable (hello, Maya! ;-). The user is not just starting that software once at the beginning of the day for a long productive day of work, they are all to often starting it again after a crash. Or after they shut it down to get enough RAM to run Excel. Or after rebooting Windows for /another/ mandatory update from IT.
I once had to restart a particular high-end compositing package thirty times in an hour. Twenty seconds of the average two minutes were spent staring at the splash screen. But I had to do it, because I needed thirty frames rendered and a particular plugin crashed after running one frame.
The user is not starting your software to admire your credits or the clever graphic design of your logo. They are starting your software to /use/ it get a job done, a job that they have in mind to do and any distraction at all (even a harmless splash screen) is a new stumbling block on their way to resuming their task.
I heard of a study done back in the mainframe days that determined that anything that took less than two seconds felt instantaneous to the user. However, anything longer (even five seconds!) took "forever". In my years of programming, I have found nothing to disprove this (possibly) apocryphal conclusion.
Your user's time is valuable. Your user's mental state and flow are valuable. As programmers on Hacker News, we all know about concentration and flow, right? Extend your users the same courtesy you expect from your tools. Help them keep things going, don't break their rhythm and don't let them lose context.