Considering the basic setup you have to offer there isn't much money to expect... I'd never pay more than €40 - €50 for that setup... and by doing so I'd feel quite desperate...
Yes, the A1200 has gone through something that looks like some kind of reviwal, as of lately... which leads us to the fact that the demand has risen slightly (and thus the prices aswell)... though I doubt it will last forever... and besides, if you decide to sell it, and after some time realise that you regret selling it, you will probably NOT have much trouble getting hold of another one in the coming years.
So... I say... if you want some quick and small cash and know for sure that you wont be using the computer if you keep it, or simply just consider it taking up some valuable space... sell it... if you regret it... buy another one... they are anything but rare... no matter what the prices on eBay looks like at the moment (I don't know what they look like at the moment). If it doesn't take up valuable space and you think you will use it every now and then... keep it.
It seems like you decision is anything but dramatic... if you had been considering seeling a heavily expanded A1200, on the other hand, then I would have recommended you to think twice before making your decision... though...
