They are mostly fairly obvious ones, many are already mentioned on the forums:
1. Stylemaster (westciv) replaces much of my use of Dreamweaver
2. WebAssist - their products are not the same as Interakts but some are very useful and they do save time. Sometimes a little buggy though. DataAssist is good and eCart is good for e-commerce and more, if not always user friendly.
3. FCK editor works well as a replacement of KTML (and seems faster too)
4. I'm still using Interakts stuff for images, but DMXZone's Smart Image Processor looks interesting, though the PHP version of their stuff always seems to be a step behind the ASP version.
5. Most of the rest of Interakt's extensions are replaced by the new toolkit. I'm looking for 1) a good calendar replacement and 2) A replacement for CSS menu's, which was good forbudget sites which didn't need a 100% custom design. There seem to be no end of charting tools out there (see php resourse index site), though I'm still using interakts at the moment. I didn't use Phakt, so I don't need to replace that one. I would like to find something that does what AJAX toobox promised (I never bought it, just as well it seems) as Adobe doesn't seem to have got the point with SPRY (though it may have improved if the Interakt team have had some input!)
The nice thing about Interakt was that everything was in one place, worked together, and had more functionality than most - however their extensions do create a mass of files when you do even the simplest task, which adds to the complexity if you want to edit code and makes for messy and complex sites for others to follow, and sometimes made small tasks a pain (which files do I need to synchronise after making a change?). That I won't miss.
The main problem I have is finding replacements that are WAI compliant. Interakt wasn't entirely, but they did much better than most. Most other solutions haven't really considered accessibility, and very few have taken it seriously. It is a weakness with WebAssist which is far too tables-based.
I mostly use PHP but also some ASP so I've tried to find solutions that handle both. I've also put my rates up 10% to allow for more manual coding, and the time taken finding new solutions. I've also outsourced more design work to focus on getting the code right. I'm not cheap but I've yet to have a complaint!
I think that's about all. I'd love to know if others have found any different solutions.
Matt