Well, I may be off-topic, howevere I feel to add on what Phill said. I 
strongly believe that art is by definition SUBJECTIVE, in fact, one of 
the most general definition of art is "a subjective means of expressing 
reality" (either the reality "inside" or the "outer reality"). In 
general, creation itself is subjective, and by that I mean that 
different people have different conceptions, which come to life in 
different ways when creating something.
Regarding software engineering: SE is byt itself a process of 
creation... which makes it pretty subjective, despite the fact that it 
involves technical knowledge (generally considered to be objective). So 
if it's subjective, it can't be science.
But that's a rather childish point of view. SE is much more complex than 
that, so making a statement like "SE is an art" or "SE is a science" is 
generally not true, considering the complex context in which it is made. 
My oppinion is that SE is a subtle mixture of rigurous science and wild 
creativity (and imagination etc etc), deep technical knwoledge and 
dedicated passion. Though let's not forget the best thing about software 
development: it's alot of fun!
Cheers,
Radu