i like things that are destined for doom i think.
for example, i own a Casio RZ-1. the sounds are not very interesting but it does have some unique features. It has individual outputs for the each drum channel and it has the ability to sample 4 very short sounds at 8bit.
Here's a video of the sounds it makes. It's been used on some classic house records.
Everytime I think about selling it I find another reason to keep it. Check this video out.
Apparently there are eproms out there but I think what people are doing is burning their own eproms with an eprom burner. I'd love to have added sounds.
Right now I just use the RZ-1 to beef up my Ableton Live performances. HOpefully I can post a video.