I'll let you know up front: Windows & Linux user. I'll openly admit, I'm not a much fan of the OSX OS, but I do watch it in the hopes it'll someday be at a place I'd enjoy. But hey, that's my opinion, and I'll certainly not foist on you -- tastes differ.
That said: Good God. I never thought I'd come to a Mac fan site and find so many people dismiss a two-button mouse as 'too complicated' or 'not simple enough' while at the same time touting **keyboard shortcuts** as easier. The mind boggles.
Also, I see a lot of people saying "If a 2-button mouse is so important, just buy" one. This is, of course, an incredibly short-sighted, bordering on ludicrously ignorant attitude. Let's explore our computing history with a little segueway into game consoles.
Sony's PS1 comes out with two controller ports. They have available, a 3rd-party device that allws up to 4 controllers to be plugged in, assuming the games take advantage of it. Percentage of 4-player games on the PS1: maybe, 5. That's probably over-estimating it.
Nintendo's N64 comes out with four controller ports. Percentage of 4-player games on the N64: 90%. Maybe higher, it didn't take long for games to be eschewed if they didn't support full-blown 4-player modes (even if some of them were lousy).
Sony's PS2 comes out: 4 controller ports.
Microsofts's XBOX comes out: 4 controller ports.
This is, as we say, a lesson of history. Something's availablity alone does not drive usage, having it built-in (ie. standard) does. Ship a 2-button mouse with every new Mac and in 5 years there'll be almost no commercial Mac apps that don't have context menus. Users won't care if there's a 2nd button, or context menus, if they don't use them. Once you get used to having them, you're not quite sure how you got by without them.
As for the control key placement, well, I can see how that would be disruptive. I'm not sure which layout is better, but arguing that against the spacebar is better because of 'proximity' is pretty lame. I frankly find ALT+key a lot more clumsy than CTRL+key because it's easier to find the corner than 3 keys in from the corner. But that probably must means either is equally easy.
Still, going by my earlier point, if you want to make things easier for switchers, I'd make the windows layout the default and let old Mac hands switch (hell, ask at install if it's a big deal). They'll know how to do it. New users won't.
What OS X Could Learn From Windows