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.
Are you having fun yet?