My new vid card is supposed to arrive tomorrow! Yeah!

In the past, I've formatted the HD whenever I've put in a new vid card, but I'm feeling pretty lazy right now.

Would you reformat or even reinstall your games after putting a new card?

No, never. Just uninstall the old drivers, put in the new card and install the new drivers.

The only case when I've formated Windows because of new hardware is when I change the motherboard. (luckily this is not necesary with Linux :p)

Video cards are more truly "plug and play" than anything I've seen that explicitly says "plug and play" on it*. No formatting needed. It's great because you can still see the screen while uninstalling old drivers and installing new ones (though unless you're switching from ATI to nVidia or vice-versa I don't think you even need new drivers. I could be mistaken though).

*it once took me three days to install a "plug and play" modem under Windows 95 on a Pentium box back in the day

I have never known anybody who would so love the process of installing Windows that such small reasons prompted them to do so.

That's like reinstalling windows when you attach a new keyboard...