Not really good ones. There are others, but I don't think they have the ROI you could get at AdWords, unless it's really low. Are you getting low conversion/click rates? Apart of that, you can try CPM networks. There are a few niches in which they do still perform well.
I want to promote a niche that AdWords doesn't allow but Yahoo and MSN do. However, they don't allow image ads so I'm looking elsewhere.
AdBrite do have CPC Image ads. Unfortunately I haven't tried them, so I cannot say how well do they perform.