A lot will depend on what hardware you decide on.
I have both a Dell AXIM X50 PDA and a NOKIA 770 Internet "tablet" (both obtained used

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I find the Dell running the TelCanto software to be easier for me to control the SB.
TelCanto home pageThe NOKIA has a larger screen and much better resolution than the PDA.
SlimServer comes with a "skin" for the NOKIA. This will allow browsing by album cover and displaying your playlist by album cover.

SlimServer & NOKIA 770 wikiNOKIA has recently released an updated unit (N800) and quite a few of the early 770 adopters are selling their unit at less than half price (that is how I got mine

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For me, I find the text based interface of the TelCanto software easier to browse through. Others may find the graphics based NOKIA skin easier. Either way they both are very good for control of the SB. The NOKIA gets the edge for your particular application.