Really interesting question. Can i recommend that you browse as many sample producers websites to get an idea of a few thing:
1. The popular formats for samples
2. The variety and diversity of samples
3. The different type of sample players.
Logic, in my opinion, is a great place to start. Immediately you have access to the EXS24 which is a very popular sampler and is included with all versions of Logic now. Explore some of the samples that come with Logic to get an idea of what's good and what's missing.
Another reason why Logic is a great place to work from is because of the ability to create apple loops. These can be essentially loops and/or samples or if you create green loops (with Logic based effects and instruments) you are providing more than just an audio sample, but MIDI notes and the ability to fine tune the sound of the loop (for Logic & GB & STP users).
Remember that there are other popular file formats like, wav, aiff, rex2, etc and other popular samplers/players like Kontact and Halion, Stylus RMX. It all depends who your target audience are.
A good place to research this would be a music magazine. Like Sound on Sound, Music Tech, Computer Music etc - and scour the ad's and visit the websites.
I'd be really interested to hear how you get on...