I would personally go for Sony Ericsson. The K810i is a very nice phone with a good camera and non-walkman music player and radio. I have one of these myself and am very happy with it.
If you are looking for a Walkman phone with a good camera as well, then the W810i is one of the last remaining Walkman phones to have auto-focus on the camera.
As you don't say what your budget is at the moment, then that is what I would recommend for the time being.
I don't have anything against Nokia, the latest models (particularly the 6300) are very feature rich, but don't seem to have very good cameras.
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