canon 70-200 f4 non-IS vs IS

[tmd77]

Ok so i've been trawling through searches and google and anything i can get my hands on to try and find one thing out - Is the canon 70-200 IS version actually worth double than what the non-IS version is?

I don't have a "style" of photography yet, as i'm still feeling my way in this hobby.

i can get the non-IS version for about $720, with the IS version for about $1,200, and with the aussie dollar at the moment it makes it quite attractive, but $500 is a huge difference in price.

In my mind i'm thinking of going with the non-IS to start with and as i get more and more experience, then upgrade to the IS version when required.

i understand the physical elements of what benefits that IS have, but what i'm looking for is the practical experience of members here who have used both the non-IS and IS versions and whether in their opinion the IS is actually worth $500 more or not?

I'd value any contributions that you might have!

thanks in advance