I sincerely hope no-one reading these answers in the future get's the wrong idea here. Hence I feel the need, four years after the original asker was here, to add some context.
What Starting Strength does
Starting Strength is designed to add maximal strength as quickly as possible whilst not specifically building hypertrophy or work capacity. It does this very well and if that's what you want do it but stick precisely to the program, it works. FYI the program lasts no longer than a month or three for most people.
What Starting Strength doesn't do
What it doesn't do for the average person is build a nice physique, or prepare you for the best strength progress in your future lifting career. It's very much a one-trick pony.
If you want to be better, be stronger, and look better than the average person who wants a bit of strength, you would be well advised to do a lot more work. Build yourself a base of work capacity, and focus on the one aspect of your training career that anyone aiming for maximal strength or maximal muscle should be focusing on: building muscle mass.
How to understand the other answers here
All these answers above about how the three day setup in starting strength is somehow better or more effective are correct ONLY if your goal is as much immediate strength as possible in the next few months, and you don't care about slowing down your long term strength and physique potential by having to backtrack and work on building a base later on once those beginner gains die and you are left stalling like a grounded whale.
tl, dr; if you feel you can do more and you want to actually make long term progress, then please do what your brain is telling you and do more.
If anyone wants further advice, how to build more work capacity, how to set up a routine to do more work etc, feel free to ask.
So what else can I do? What program lets me do more?
Check the link in that article to download the complete package of programs, which has a well laid out beginners program that has you training 4 days a week and doing 4 main lifts (S/B/D/OHP) in each session plus accessories. If you want to do more, here you go.
And through that link you'll find a powerlifting world record holder's informed take on how to master your training career to get as strong and as big as possible. Covers beginners, intermediates and advanced.
To anyone confused by my views, this should be an interesting read. Hope it's enlightening.
Do you have anything else? I don't jive with that program
This one here is another awesome program and just so happens to be Mon - Fri: http://www.powerliftingtowin.com/forums/viewtopic.php?f=14&t=1726