12"iB rocks...
I have had my 12" iBook since March, I love it.
This thing is more than capable as far as computers go, for what your demands will be, and if your demands of the computer get bigger, it can handle it. That has been my experience so far, my machine more than keeps up with my increasing demands on it, no hitches.
Just look at the post above mine, he is comfortably treating his 12" iBook as a desktop without any problem; he is running an external large monitor, wireless key board and mouse)... in addition you cannot beat the price... if you have the time, and the dollars, for an extra $125, special order it with BlueTooth, built in ($50), and the optional 60 GB hard drive ($75), so you that the iBook can more easily grow with your needs to do that kind of stuff...
I'll tell you what, that 12" iBaby, is one of the best values you can pull out of the Apple Store, IMHO...
As far as screen size itself goes I am so happy with the size that when, it comes time to upgrade to a PB, I will probably stay with the 12" size rather than go for the 15" PB that I orihinally thought would be next...
I am very happy with mine, and can thoroughly recommend it...
Just my 2¢ 😉