I've been streaming from an iMac using a Moon 100D with an Airport Express for eight months and the sound is exceptional. I've been so happy with it that I went to the Moon 300D using the same Airport Express.
I use a glass fiber optical cable from the Airport Express to the DAC, though that's probably the least critical component in the signal path.
I don't have any experience with the Squeezebox Touch, It has a lot of fans but I don't think you'd be disappointed with any of the Apple products. The Apple TV would give you other entertainment options but I haven't tried one yet and don't know how it compares sonically with the Airport Express.
I use a glass fiber optical cable from the Airport Express to the DAC, though that's probably the least critical component in the signal path.
I don't have any experience with the Squeezebox Touch, It has a lot of fans but I don't think you'd be disappointed with any of the Apple products. The Apple TV would give you other entertainment options but I haven't tried one yet and don't know how it compares sonically with the Airport Express.