Bakapo - you don't need a power pc to do AI stuff, so a decent laptop with a 15 or 17 inch screen would be all you need.  Like Len said, lots of good deals out there.  I would stick to a good brand name if you want something reliable.  Let me know if you find something in your budget and I'll help with some reviews if you like.  I'm also impressed with the stuff you can do just on your phone, thanks for the Wombo fun, you always get me going back to it and trying new stuff, lol...  ;)