The smartest purchase I can think of would be a very average digital sampler with lots of ram in it, and a scsi drive stuck to it. The downfall to this setup is that you would need to find your own samples. A good example is the E-mu ESI-2000 or 4000. Nobody seems to want these and you can fit 128 megs into them so you get, 17 minutes of sample time, or something like that.
If not, I guess the everyday rompler would be the good choice, something along the lines of some Roland JV series or a Korg something. Something made in 1996 so the price is pretty low and the sounds are good enough for what you need.