Illustrator CS5. I have been a prepress tech and graphic designer for letterpress exclusively for 6 years (the old Quark days through CS5), If I was working in the 4 color process world I would probably be more inclined to use indesign. If you take the time to learn how to use the Pen tool in illustrator, you will learn to love illustrator-
Indesign has export limitations that make it my least favorite part of CS5- I convert and prepare files that come from lots of different designers and lots of different programs – Illustrator is the most RIP friendly –
Bev Dittberner
Full Circle Press