I have 2 C3's (not as laptop) mainly for web browsing, mail, music and not to heavy work. They work excellent, low noise, low power.
I Have 2 laptops 1 p3- 500 and 1 amd 1.8.
The plus on the C3 is, it has USB-2 and Fire wire. That has the advantage, that you can almost everything connect to it.
Since last year, we don't buy machines with all kind of stuff in it. We buy machines with at least
some USB2 ports. Then you can buy HD's, CDRW etc and you can hang it on the machine you want. Keep in mind those things are mostly only an hour a day in use. An extra advantage is that if you buy another one or a desktop, you can use all the usb equipment.
Fire wire is nice but it is not so much in use as USB.
Both machines are good, but without USB2 in my opinion it is a bad investment.
I woul buy some RAM. I have in all my machines at least 500 MB. It saves a lot of time.