So, in case anyone is curious about it... I will go with the setup as listed in my first post now. I will probably only get a single display initially, and get the other one later the year, though.
I actually got the very same display at work today (and snatched the DVI cable as a future backup, just in case, since it's useless for our work computers

). It's very cool, indeed! Two are almost overkill for desktop (<- the virtual one) space.
As for the OS, I will got with Vista Ultimate 32bit. It's not really that expensive at € 150 (not much more than the Business version, and only about € 50 more than Home Premium). If I find myself really wanting a 64bit OS in the future, I will just have to buy it again, I guess... but it's probably just not worth the potential trouble for a good while still.
Thanks for the helpful comments. Certainly helped me a lot with some of the decisions.
Bye
Thanee