Just found a passable 64 bit disassembler.

[jj2007]

Update on X64Dbg: If you insert an int 3 to force a break at interesting points of your code, the debugger won't allow you to continue with F7/F8/F9. The solution is to press Ctrl F8.

[fearless]

I was chatting to mrexodia on the gitter channel they have (https://gitter.im/x64dbg/x64dbg), and mentioned this to him - he did state that this was by design - and referenced issue #211 (https://github.com/x64dbg/x64dbg/issues/211) - he did mention emails, so i presume you already spoke to him about it anyhow.

Worth mentioning the full source debugging in x64dbg and in the most recent additions the ability to toggle breakpoints from the source view (feature request by myself), and you can use F10 and F11 to step source lines, which is pretty cool.

[hutch--]

I took sinsi's suggestion with ArkDasm and have been very pleased with the results. Clean dis-assembly, differentiates each procedure clearly and will single step through the exe with F10.

[mmxmax]

I took sinsi's suggestion with ArkDasm and have been very pleased with the results. Clean dis-assembly, differentiates each procedure clearly and will single step through the exe with F10.

I also tried ArkDasm. Its pretty cool especially renaming functions and adding multiline comments and the possibility to create memory snapshot.
Some debugging Windows are a bit hidden and need to be enabled when debugging starts e.g. Debugging menu -> Windows -> General registers or View -> Hex View (for memory view)

[mineiro]

Have fdbg too by feryno, I'm using it on linux but have used it on windows side too years ago. Have source code using Flat Assembler.
http://fdbg.x86asm.net/