Yeah those are about the same specs...well actually... are the same specs my 1st PC had after it was rebuilt from a 200mhz. It was the Thunderbird (was actually quite stable) and I had a Geforce 2 MX400 64mb card in it. Ran rather well for quite some time.
It would run World of Warcraft I'd say yeah. Not long since I changed that system to this one... Though its still here, just not built yet again in its old pride and glory.
I'd say that would be worth about £150-£215. Its not a bad system and would be good for a person who wants to play some simple games, and do a bit of work, and wuld serve some purpose, though I wouldn't be prepared to pay any more for it I'm afraid, even if I did have one just like it (stable as she was)... I say this because for about £500 you could build one about 2 and something times better than that
Let it go to a good home and it'll serve alot of time there