Earlier quoted context omitted.
> There are more alternatives to IDA Pro. Hopper Disassembler is one. Binary Ninja (binja) is another. Sure, but radare2 is open source which cuts both ways I suppose. IDA feels significantly more polished than r2, but I've had fun implementing a not-so-common-anymore architecture as a set of r2 plugins. There's also the free version of IDA (x86 only though).
I think the new free version of IDA also supports x86_64 now.
>IDA Starter: supports more than 20 processor families, including the popular x86 and ARM processors.
>IDA Starter does not support 64-bit files.
Doesn't look like it does.