I couldn't agree with you more. Horizontal scrolling is idiotic, and no, Apple no longer lets you turn it off.
Before 10.5.5 you could turn it off in System Preferences, but no longer. And iLife '09 forces you to use 10.5.6 if you want the benefit of iLife '09's features--even if you absolutely hate horizontal scrolling and don't want 10.5.6.
For me, if I wanted to move off the left margin in a program, I'd go into System Preference and enable it, you know? It's worst in Excel 2004 (and no, I don't prefer going back and forth between Office and Numbers to be compatible with PC heads). Apple, just give us back the choice to turn it off!
If you agree, make your voice heard here (
http://www.apple.com/feedback/macosx.html).
And while you're at it, ask them to allow users to disable "font resizing" in Safari and other programs if we want.
Apple's tried to say that font resizing in Safari on the Mac using pinch and zoom gestures is just like the iPhone, but it's not! It's annoying, happens anytime you leave your thumb on the trackpad and isn't something most people want to use as often as minor accidental inputs call it into action.
This forced migration to horizontal scrolling, lame font resizing zooms and loud trackpad clicks on the new Macs have for the first time in 10 years shaken my confidence in the direction Apple is heading. I don't want to be forced into self-consciousness or "thumb policing" in the way Apple seems to want to force all users.
A sad day! Though if you like those things, cool. I just want the ability to turn them off because they don't work for me.