[dflock]

If you're not editing them, then lnav is what you need: http://lnav.org/

[tstack]

For reference, a 435MB web access log with about 3 million lines takes:

* lnav about 4 seconds to index[1] and display

* vim about a second to display

* emacs about 3 seconds to display

This is on a late 2013 27-inch iMac with a 3.5Ghz i7 and the file cached.

[1] - Indexing in lnav involves parsing all log lines to extract their timestamp and log level (status codes in this case)