[papereditor]

Yep. TextView is a beast.

For multi-megabyte files I always use Sublime.

[KerrAvon]

BBEdit is more Mac-like than Sublime and handles multi-gig files with ease.

[papereditor]

Indeed, there are a handful of those dev-oriented editors that crunch through mega files with ease. No idea why I prefer Sublime. :D

[kccqzy]

And for multi-gigabyte files I use HexFiend.