Gigastudio reads Akai and gig formats. Kontakt and Halion are able to read most formats like Roland, Emu, Kurzweil etc. All able to convert wav formats with a little bit of programming. Note that conversion may not be 100% accurate. To convert a sample in another format, it needs to convert the detailed programming like cc controls, release samples, key-swtiching, cross-fading etc. When you go deeper into things like K2 scripts and Gigastudio iMidi rules, things will start to get messy. Most "simple" sampels are able to convert without problems. My Gigastudio converts Akai flawlessly.
The other thing is that there are now more and more standalone VSTi samplers that do not need a dedicated softsampler to run. That makes things slightly easier and cheaper.
Also, more and more developers are coming up with libraries in multi-format version (Giga, Kontakt, Halion and EXS all in one DVD-ROM).