Career Girl,
I think its well worth doing and Duir has indicated some of the good reasons why.
I did the IMC a couple of years before the IR but I have some very specific advice based on that experience.......
Make sure you do your IMC with an Instructor (and preferably school) who is teaching the IR as a full time Instructor. If you are going on to the do the IR at some stage afterwards you don't want to have to break any bad or lax habits that you have picked up on your IMC.
Even if this means your IMC costs more, it will save you a far greater amount when you are doing your IR training.
Talk to people who have recently got IRs and ask for Instructor and School recommendations.
Good Luck,
QNH 1013