If Sansa doesn't suit, I would up the budget a bit and look at Sony NWZ (S, A and E ranges) at around $100 upwards.
Sound, battery life, build quality, interface, no iTunes-type annoyances transferring files. On top models, headphone quality good enough that you'll save because you won't want to replace them.
Downside -- no memory expansion, no firmware updates. Sony not the best to deal with.
I will take a look at the NWZ.
Just really surprised at the dearth of options at a reasonable price.
The market niche is just dying for someone to jump in there and make a whole lotta money.