>>16
Even for other platforms, even on current generation handhelds, C++ is the language of choice among professionals. GCC 4.5 is currently used for the PS3, PSP, Wii, and Nintendo 3DS pro SDKs.
Professionals don't use Allegro and SDL, unless they're doing a quick Linux port, in which case they'll use SDL to setup an OpenGL context.
Allegro is an abomination that should die, it's an early project of Shawn Hargreaves who has since gone on to work in the actual gaming industry and now works at Microsoft as the chief architect on XNA. He's matured as a developer over the last 12+ years. Compare Allegro now against the design of XNA and you'll see a huge difference.