I've been using Adobe since 1991, Windows and Mac before then, and still struggling to be a Linux convert (I'm one year in, but still not Windows free... give me strength my brothers, give me strength!).
Photoshop: Sorry can't stand it. Nor any of the replacements. I keep praying Adobe will make Fireworks open source. Fireworks is just so much easier to use. Adobe, are you listening?
Illustrator: No decent replacement. A very good application though.
InDesign: You know what... I've actually found the OpenOffice is an amazingly capable replacement for InDesign. It nicely fits the 80-20 rule and has some features and capabilities that InDesign still hasn't been able to do in 18+ years (like formatted bullets with spacing.) The only problem with OOo as a replacement is backwards compatability issues in ODT documents between release versions. But then so do Adobe products.
The perversity of nature is nowhere better demonstrated by the fact that, when exposed to the same atmosphere, bread becomes hard while crackers become soft.