Take a look at this thread that I started quite a while ago:
purchase choice - 2003 S or 2005 2.7?
Essentially the same issue as your inquiry.
I ended up (just recently) going for the '03 S. Deciding factors for me: I did not really prefer the new interior styling, nor the changes to the front end appearance - they were neutral factors, if anything. I did prefer the additional torque of the larger motor, as many members commented on. I had more cars to choose from, and was able to find one in excellent condition even though it was older. Purchase price was lower.
drburton is correct - the 05' S is the 'best of both worlds' if you can afford it.