re: A terminal: probably fine, albeit small. Running at 2880x1800 without any scaling isn't terrible, but it would quickly drive your eyes to escape your skull. I can't say for sure what would happen under Linux given only a terminal, but I imagine things would be pretty small until you got it using a different resolution than the native resolution.

Terminal emulators are fine, but I assumed you meant the other kind. Terminal emulators look great, as does every text editor I've used (MacVim, vim in a terminal emulator, Sublime Text 2, TextMate 2, Xcode [looks great, but it's unfortunately still a lousy IDE], etc.).

re: Dual boot, also fine in my case, though I only keep Mac OS and Windows 7 installed right now. Windows 7 in particular is an issue, as DPI scaling only affects some programs (so where on Mac OS you'd get pixel-doubled views or text, on Windows you get windows that aren't scaled at all, such as Chrome). If you have dual monitors, Windows is particularly painful, as DPI scaling is system-wide rather than per-screen. I haven't tested Windows 8 and likely won't until after it's been released.

The best route I've found is to simply set the display to 1920x1200 or lower and scale it up on Windows. Windows 7 just doesn't handle high resolution stuff particularly well -- it's not bad, but things just aren't all there. I expect Windows 8 will be better.

I couldn't say what your options are on a desktopless Linux/BSD system, but I would imagine that there's something you could do, even if that something is just using a larger font.