You don't need a wireless network to use a Squeezebox. I went for the wired version and had CAT5 in my last house. In my current house I have a single wire running back to my study where the server and hard disk are.
Another thing to consider is the way a Squeezebox will change the way you listen to music. Once you have ripped all your CDs, and presuming you have set up genres and not ripped the tracks you would normally skip, you can use the random function (which can crossfade too!) and listen to music to suit your mood. It will sometimes play music you haven't heard in a while.
I think the benefits (if any) of a high end transport are far outweighed by the flexibility of having all music on hard disk.
As I run my SB2 into my 561, I get the best of both worlds.. a flexible music library played by high-end DACs.