You know, I'm not sure how early in the boot process the drivers are consulted, but if that is the issue its by far the cheapest easiest fix here. Some of those drivers are subject to automatic updating, depending on your system setting, and if a new one just came out a few days ago, it could explian the sudden change (again if they are actually consulted at the very beginning of the boot).
So first thing -- there should be a relatively easy driver rollback or driver choice function in the software for your video card, if the screen allows you to still read enough of it to find it. You could try that and see what happens after reboot (they always require a reboot). If it makes no difference, then I would make a point of immediately returning the driver to whatever it was before you changed it, just so you don't forget and to eliminate a potential source of error as you check other problems.
Second thing, given that this is a laptop I assume this was an integrated video card? I just ask because if it were a desktop, and you had an add on video card, you could go into control panel (if you are using Windows) and change the card you were using to the integrated one instead (assuming the board came wiht an integrated one), and in that way potentially eliminate (or confirm) the video card as the problem. If nothing changed, then you could rightly guess it was probably the screen itself, or *gulp* the motherboard. If the problem went away, then you would know it was video card specific.
I found the hippie!!! You're lucky that you have my same first name, I will still let you be cool.
J/k Macs are okay for artsy people I guess.
