I think the old Emu Emulator III sample bank CDROMs are excellent. A lot of work went into those sample-banks. Until I recently re-fired up my EIIIxp, I forgot just how nice they were (and how nice real hardware sounds and plays). The 2Mb samples of strings, pianos, instruments, percussion are very musical, responsive, w/ a lot of thought to modulation control for expressiveness. Ones I have:
#10. Elements of Sound 1mb collection
#11. Elements of Sound 2mb collection
#12. ESI-32 150MB Production Soundset
#13. Dance 2000
#16. Twenty Six Studio Drum Kits and Percussion ESI-32

Many of these are now available for cheap: http://shop.ebay.com/i.html?_nkw=+EIII+cdrom
The "NorthStar" collection http://www.northstarsamples.com/ProductIndex.html is awesome if you can afford it....

I wish there was a way of loading these pre-existing sample banks into a linux softsampler or translating into soundfonts. Of course, you'd invariably lose a lot of the useful programming (filters, envelopes, multisamples) that went into engineering these "pro" samples, in conversion.

Are there any linux softsamplers that can access the massive library of pre-existing samples. Or Linux sample  translators equivalent to "Translator Emulator X Convertor, by Chicken Systems"  which will convert "Akai S-1000/3000, Akai MPC, Emu EIII/ESi/Emax, Tascam GigaStudio 1 + 2, SoundFont, Native Instruments Kontakt 1 + 2, Steinberg HALion I and I". 

Or best of all, an open-source version of the "Emulator X3" http://www.emu.com/products/product.asp?category=501&subcategory=168&product=17681 :-)

Niels
http://nielsmayer.com 

PS: or you can just sample frozen lakebeds, solar winds, and spaceweather: http://silentlistening.wordpress.com/2008/05/09/dispersion-of-sound-waves-in-ice-sheets/   http://cse.ssl.berkeley.edu/stereo_solarwind/sounds_examples.html , and http://spaceweatherradio.com/