First question - what frequency range do you want to cover for the RF equipment?
Second question - the "good stuff" is sometimes the most expensive, so sometimes there are tradeoffs. Are you looking at new equipment, used but still-being-made equipment, or used no-longer-in production equipment?
In general, for RF equipment, Agilent is the most popular choice. For oscilloscopes - Tektronix. In General! With more specifics of what kind of product/frequency range/equipment purpose better pointers to specific equipment brands might be made.