We use Motorola SP50 radios. They're a commercial variant of the earlier "Spirit" radios. We've found them to be bulletproof, though I think this model is now being sold as something else.
Outside staff and management also use the earbud/lapel mic attachments. They work very well in varied noise environments and provide privacy.
If you don't want to go new, you can usually find these radios on Ebay. Just make sure you get the same model number... there are some differences (wide band/narrow band, number of channels, power output, etc).