The adobe creative suite is the most invaluable tool I use at work, particularly Illustrator, I produce a huge amount of vector illustrations and spot colour work. For the average home user all that matters is what it looks like on screen, but for the people it is actually designed for it gets much MUCH more technical than that. Even a lot of highly trained designers don't seem to have any idea about how to prepare work like this for the press. I spend an awful lot of time fixing work from people that only know how to make things look pretty so that it can actually physically be printed using the processes they were expecting.
Your average design school graduate doesn't have the first clue how to prepare a piece of 4 col process + 2 spot work, or the various and lengthy technical requirements that go hand in hand with that sort of work.
When it gets to press I have to be absolutely sure that the printed results are exactly what I was expecting, there is no other software I trust in that respect. Illustrator is an incredibly powerful and complex piece of software, I don't consider it overpriced at all.