I have used Monaco for all my fixed-width text needs since I can remember. I do everything in Monaco – write emails, use terminal, TextMate, everything. I remember I used to use IRC in Monaco in fricking 1994. I love Monaco. “That awesome font on the Mac”, I used to think of it as.
But lately my eyes have been tiring while staring at TextMate all day so I’ve been tweaking a bit to try and reduce eyestrain. Changing syntax colouring, reducing contrast here, increasing it there – that kind of thing. Seems to work, a bit, I guess. But as part of that I also decided to check out what other fonts people thought were good and by that route I came across Inconsolata, perhaps the first monospace font I’ve ever thought was even comparable to wonderful, wonderful Monaco.
The problem is the serifs on Monaco. The lower-case “i”, for example, looks fantastic without its left bottom serif at 10 points. I maintain to this day that 10 pt Monaco is the single best way to represent text ever fucking invented, but at 14pt (the size I use it at in TextMate) the serifs that look so kewl at 10pt start to work against it a little.
Inconsolata is basically Monaco with a few tweaks that make a surprising amount of difference. I am not some kind of beret-wearing font expert, so I have no idea how to describe it, but at 14-16pt I find Inconsolata slightly easier to read than Monaco. My terminology is probably completely wrong, but it feels like Inconsolata is “hinted” slightly better – one doesn’t need to stare at a word quite so hard to discern its composition. The lower-case “i” is a good example – the serifs at the bottom, and slightly different spacing, make it more obviously a lower-case i at a glance. It’s subtle, but when you stare at something for 6+ hours per day even a subtle improvement becomes more than worthwhile.
Anyway, it’s a free & open source font and an easy install for OSX – download the OpenType file and just double click – so if fixed-width fonts are a big part of your day, I recommend giving it a shot and seeing what you think.