i also prefer one-button mouse.
we use windows at work and i use macs at home, and i have to constantly use both mice types. here's what i have found:
1) with one-button mouse, you think more. you intuitionally know that the mouse is for clicking and the function you're looking for in the software can be used with a click. if you're looking for a context menu, you know you have to press control button before you click, so you do. one keypress, one click, problem solved. with two-button mouse, you get confused even if you don't admit it to yourself. when you're looking for that context menu, you sub-consciously first press the primary button and then the secondary button, and while it gets the job done, it's awful that the mouse actually prevents you from thinking what you do. even if you don't admit it. with a two-button mouse, you click more and think less. with a one-button mouse, you click less and think more.
this is not a theory. it is an observation. in my office we work as teams, one team in a big room. when you stop working for a while and get a cup of coffee, sit back and listen, you hear constant clicking but when you look at the co-workers' displays, almost nothing gets done. clikety-clickety-clickety-clik... it's just mad. when i visit my friend's advertising agency where they only use macs, i can see things being done and they click a lot less. why? because the one-button mouse makes them think about what they're doing.
2) with one-button mouse, the software developer has to think more. every function of the program has to be usable with a single-button mouse, as that is what apple ships with its products by default. you cannot hide functionality anywhere, it has to be easily accessible. contextual menus are for special occasions and not a holy grail of a nice-looking interface as it is in windows world. this fact makes better software for us users. this is something nobody can deny.
3) slightly off-topic, but let's think about the scroll wheel which is quite a standard nowadays with the two-button mice. who was the moron who first implemented this piece of crap? i admit, it's sometimes useful, but again: within the two-button mouse (which makes the user think less) it's a disaster. when you think less and less, you will also think less about the scroll wheel use. i can often see that someone is scrolling through a very long document with a scroll wheel - not only that makes an awful noise, but it will also destroy the user's wrist. why on earth don't the users think about when it's good to use the scroll wheel (going down a screenful of text) and when it's not? the answer is that the two-button mouse has already dumbened the user NOT TO THINK about how the mouse should be used as a tool, and that dumbened user cannot see anymore that one could grab the scrollbar and drag it down in a second; instead of the good solution, one just keeps scrolling down little by little with the scrollwheel, not minding if it takes a minute instead of a second. it takes a doctor (and several weeks sick leave) to get the user convinced that one has bad mouse habits.
here are my findings about the mouse. i really sincerely think one-button mouse is a blessing