Hoorah! I managed to fix BG&E, and i've just been powering through it. For anyone who's interested, this is what I did (and why it worked);
I created a profile for it in ATI Tray Tools. In this profile, I set it to force Vsync on, and set it to 60. The reason this fixed my problem is because as i've found out, cutscenes and voiceovers ingame seem to be rigged to run perfectly at-or-below 60fps (60hz...), no idea why, it just is (confirmed by viewing the framerate as a cutscene played, and finding that once the FPS started passing 60, the sync started to fail). So anyway, by setting that to 60, it fixed the problem... I know what you're thinking, "60hz? Are you mad?!", answer; no. I use a 21" Trinitron CRT, so if I were really running 60hz, sure, i'd be a mad bugger. Fortunately there is a strange thing happening here...
I use the refresh lock option in ATT to force every resolution that I use to 100hz. Essentially, the only resolutions/refresh rates my system is capable of are 800x600@100hz, 1024x768@100hz, 1280x1024@100hz, and 1600x1200@100hz ...nothing else. This seems to have had the strange effect of locking my monitor to 100hz, but making the game thing it's Vsync'ing at 60hz, effectively limiting the FPS to 60 ingame. It sounds wierd, but it works, and the game is completely playable.
I've been having mad fun...I just reached the part where the Lighthouse, well, y'know