I would say it depend on your maintenance budget..
P-car don't break often, but when they break it can cost alot..
maybe your better with a more recent non-s than with an older S model ?
also if you like a luxuery interior look, you may enjoyr the 987 (05+ boxster)..
if you prefer the more classic look you may enjoy more the 986..
I personally had a 99 non-s, and a 06 S..
Take your time of thinking of what option you want.. alot of thing had been enhenced in the 987.. for a quick example the traction control is now include in the base, and is not alot more smooth than in the 986 boxster..
take your time youll find 'the one' ..
good luck in your buying..