I've tried about 6 digital cables. Started with Harmonic Tech cyberlink copper, then Cardas Ultrafast, Audiomagic Scepton, Virtual Dynamics Audition Digtial, Kimber Illuminati D60, then an Audience AU24 and now currently have a Stereovox HDXV. Each was better than the prior except for the Illuminati which just didn't do it for me. I just ordered and active digital gold w/ nextgen copper plugs from Aural Thrills. We'll see how that works out! The stereovox is VERY nice though and right at your $100 limit. I fear the only issue I'll have with the Aural Thrills cable is where to ground the Nixon side of the active cable, since the Nixon is all ABS that could be tough!
Whoops, forgot two, I also have the Nixon digital cable, which is OK, I use it for my DVD to pre/pro right now. Also, I tried the Boulder digital cable with bullet plugs which I didn't like as much as the VD Audition.