If I develop a .Net application that’s going to run on WinXP and Vista, as well as on a modern Mac or Linux under Mono, what are older versions of Windows where I will have to start thinking carefully if I want to support them? Does Windows 2000 for example run .Net and is it capable of any version of the runtime? Usually, older systems mean older hardware too, which might also be a problem, I guess.
Edit
Reading Joe’s answer made me rephrase my question in the title. If Win 2k already has a lower common denominator with XP than Linux, that pretty much settles it for me. However, I’m still open to more info.
Version 2.0 of the framework is the last one supported on Win2k. We’re also less than 18 months from the end of support for Win2k.
Do you want to support win2k, or do you NEED to support it?