How do I create a natural UI to let the user choose an unlimited value? Take for example, Bittorrent's bandwidth configuration:
Arguably, putting 0 for unlimited is not natural. Some people might interpret 0 kB/s as not downloading at all - quite the opposite of unlimited. Yes, I know there are instructions saying that 0 specifies unlimited download, but the great Steve Krug says no one should be forced to read instructions.
I'm running into a similar problem in designing my video transcoding website. I have a slider, whose value ranges from 320x240 to 1920x1080 to original. I think, currently, the original resolution is hard to discover. Does the user really know that scrubbing the slider to the right end will trigger the original setting?