It comes down to what your used to using really. At uni and college it was all Adobe stuff and every studio I've worked in have used Adobe.
I worked briefly in one place that used Corel and I just couldn't get the hang of it at all, owner didn't have the time for me to sit and learn it so bought a copy of Illustrator for me to use instead. I left 2 weeks later as the guy was an arse. haha
Like you say Pixels Ink, its what your used to and what does the job for you. Design agencies I've worked for in the past have always used Abode products or Quark so thats what I'm skilled in. I use Adobe CS2, does CS3 warrant the upgrade? Be interested to know your opinons.
I am new to graphic design after deciding I want a career change (don't get me wrong I've always had a healthy interest in design, it's not like I decided out of thin air!) so am learning things for myself and managed to get the master suite so have a lot to learn. I've never used anything else and when I was doing GCSE Graphics it was all done with pen, paper and scissors (and the odd felt tip pen)!!
I don't know how I'd get on with any other software...