This is really for anyone, including the 8-Bit Guy...what are the tools you use for programming Assembler for the C64? I've read about many tools that can be used but after seeing the youtube video on Planet X2, I'm now interested in what tools were used.
Personally, I like 64TASS, as it's a very powerful and complete assembler.
Many people also use CBM PRG Studio, because it's a good all-in-one package, although I've found some quirks here and there that make it more frustrating to use than I'd like. So these days, I write my programs using Notepad++ for source code and Petcat for BASIC, and 64TASS for assembly. (Petcat comes with VICE. It converts ASCII BASIC source code to tokenized BASIC.)