Look at the korg krome. I hear it has a 4gb piano sample.
4gb total samples.paino (around 2gb).less samples than Kronos .no Japanese and other grands.only german.
Krome 88 - 1599$ (better piano sample/touch screen)or Yamaha Mox 8 1699$ (better acostic sounds)will be usable workstations if you want new (they are also light-32lbs)Stay away from Krome 61 (floppy and frigile keys ).
Yamaha p155 or even Cp33 if you want good weighted 88 with good piano sample.( $ 999).both will have better resale value than Casio .Kurz Sp5 -great but around $1799.
If you want an arranger and can live with nOt so great and less(61) keys Yamaha psrs750 (1100$) and korg pa 600 (1000$) (both actual out the door prices) are good choices.