Speaking as a recent convert to DI from traditional SLR and films and scanning to get my digital images -- I would go for at least the 2MP camera. You can always REDUCE the image size [in the file size sense] and throw away some of your lens quality,BUT you can't regain quality from a crap image of the 640x480 that the webcam limits you to.
my personal investigation shows that my Minolta S304 at 3.3 MP produces cleaner and more detailed images than even Nikon 4000 scanned slides/colour negatives from my Nikon SLR.
Anything less than 2MP will leave you frustrated in a shortwhile is my opinion.
For web site photos I would buy the really cheap Style Cam Blink by SiPix. £35.00. Its only problem is that you must put in a new battery AAA size befor you go out as flat battery mean no photos retained in the camera. (CMOS chip storage). But it will give you photos at 640 x 480 (about 100)or (300 at web sizes) 320 x 240 what more do you need especially if cash is a question. I use mine as a very light weight, hanging round the neck camera for when I go out walking. I find it just great and I have no worries about losing it, as has happened in the past.I got mine from Amazon UK
It is true that if you only intend to take nothing more than pictures for a web site, then a 1.3Mp camera will suffice.
However, I agree completly with imarcus with he said that anything less than 2Mp will leave you frustrated. I am sure that at some time you will wish to take pictures for printing, and the low resolution cameras will leave you disappointed.
If you want some recommedations in this category, post again, giving us an idea of your budget range.