All extract recipes, except for lagers, are about the same level of difficulty. So, to answer your question with a question, what do you feel like drinking?
Since you've got a pale ale and amber, I think something totally different would be great. Say, an English brown ale (I have a recipe posted for a good simple one in my recipe pull down, under my avatar), or a stout if you like them. Or go really light and go with a cream ale (similar to an American lager).