If I install, say, Mandriva or SimplyMEPIS, or indeed any other modern distro, and afterwards install hardware that would have automatically been detected by Windows e.g. a NIC, will Linux pick it up automatically, or is there some configuring to do?

I ask because I've a Wanadoo LiveBox hooked up via USB for my broadband, but I know it needs a Cat5 hookup to a NIC for Linux. Depending on response whether I go ahead and install a distro, or wait till I reconfigure the LiveBox via a NIC.

Hope that makes sense.

Cheers as always.

PS - I take it during install that I'll automatically get an option to dual boot with XP...

I am not an expert at this, and I do not fully understand what you plan to change, but if the hardware you add or change does not include the motherboard or processor, I think you are OK loading Linux whenever you wish. Changing or adding a NIC is minor, and I believe most Linux distributions will handle this without issue. (If it is a "manual" distro like Slackware, you will need to do some set up, if it is an "automated" distro like Mandriva or SUSE, you may not have to do much of anything.) If you plan to change motherboard or processor, I would recommend making the hardware changes first and installing Linux later, since the processor type may change the kernel that should be loaded by the distro, etc.

Yes, you are correct that the installation program for most Linux distributions will allow you to set up a dual boot system. In such a case, it is always best to install Windows first.

Is your last comment assuming a clean/new HDD? XP is already installed...

Most "mega-distros" (like the two you mentioned) should handle things like NICs ok. I installed Mepis using cat5, then added a PCI wifi card after the install when I had the PC in its final location.
Recognised it fine - needed configuration, but that's a separate issue entirely.

Installer will recognise M$oft installs, and create the needed options for dual-boot.
Note that this is a function of the (distro) installer, not the bootloader itself.
This is why the recommendation is to install XP first generally.

If XP is already installed, then you are good to go. (That is the way I meant it anyway.) Strictly speaking, the state of your hard drive is not an issue except that you need some room to use for the new Linux partitions. (Many setup programs will help you do this.)

Funny noone mentioned hotplug... 'cause that is the most importang prerequisite. But worry not: every distro has it. Well, Gentoo does not use it by default. But has it nevertheless.