As far as text editors go I don't realy mind much depends on if I just need to make a quick edit or if I need to make extensive changes. For small stuff I just use ed. anything more than a few lines I will use vim or if my machine is behaving itself sublime editor.
It's all wrapped in a Forth program that runs a simple menu loop. I can edit the source, assemble and run the tap file in fuse all with a few key presses.
Low-fi but I am lazy. One of the advantages is if I want to change my emulator, assembler or text editor I can and it won't break my workflow.
Forth is a great systems language - I could have written the same thing in C but it would have been a lot more painful and less flexible.
by entering a 3 char code i can load any program usually use or sequence of commands.
SevenUp or Zxpaintbrush for the spectrum graphics. but there is a more general tool called Grafx2.
If I want to prepare stuff for pdf I use latex. Once you get over the learning curve for tex its actually a very powerful language.
For music I prefer trackers, Milkytracker is great for modern tracking. But I also like sunvox. That said sunvox needs a more modern PC than what I have
Beepola is great for spectrum projects. But really there are some great trackers for the spectrum.
I use Fuse for the emulator, I get salty at some of the limitations of it but I can't think of a better alternative for the moment. I like the fact I can print out my programs to a text file. One thing I cant figure out is how to print the graphics characters in this way though. It would be nice to be able to generate a pdf with the graphics characters left intact.
The system I use with Fuse is a +3.
Assembler I use the command line assembler for Zeus. I find it to be the most powerful of all spectrum assemblers. I wish the IDE would work well in linux under wine but I have hope one day that will get fixed. The thing I like about Zeus was you get a ton of examples to show all the different parts of the assembler. At first it feels like a nagging partner because it asks a lot of questions about the project but once the task becomes complicated you realize it makes seance to know everything from the start.
Spend time at the start setting stuff up with Zeus makes later development faster.
Pasmo is ok for testing stuff out, but for a big project I would say zeus is a better choice.