Good microphones can last for years and sometimes fade in to the background while more pressing needs (such as HD Radio) get most of the attention (and capital). But after you've improved the sound of the station perhaps it is time to reconsider the old microphone standards to which you've become so accustomed.
One way to stand out and above the competition, in my opinion, is with realistic microphone sound. Listeners are more familiar with the sound of the human voice than anything else, and with a little effort and the right mic an announcer can sound like he or she is right there in the car or at home with that listener.
There are several trends in microphones that I'll cover. One is the move toward high-end condensers and dynamics. Another is toward mics that have a retro look or feel to them. The third is the integration of a mic with new recording techniques and playback media.
Large-diaphragm condenser mics are well known for their ability to pick up fine high-frequency detail. With on-board amplification they typically have higher output levels and consequently will need less gain in an external part of the system (such as a console mic preamp or processor). The net effect is a lower noise floor, and hence finer detail.
One would think that this kind of mic would only really be useful in an application that allows for the transmission of quite a bit of high-frequency information, such as FM or HD Radio. However, my experience is that condenser mics make a substantial improvement on AM radio as well, where high-frequency content in the vocal range is extremely important for intelligibility and presence.
Shure offers the KSM44, a multiple-pattern, dual large-diaphragm microphone with a low noise floor. Some of the features that should be of interest to broadcasters are its low-frequency response, its high-output level, its ability to withstand high SPL levels (screaming jocks), and its inherent rejection of RFI and common mode noise. Perhaps most importantly, it includes an integrated three-stage pop filter (for p-popping jocks).
Audio-Technica offers the AT4060, which is a large dual-diaphragm condenser mic with a built-in tube amplifier. It features low noise, a high output level and a maximum input level of 150dB SPL (for 1 percent THD). The pop filter is external and offered as an accessory.
AKG offers a wide product line, but in particular are the C414 B XL II and XLS, which are the latest versions of the AKG classic. Like other condensers it has a low noise level in the output, and an ability to withstand a high SPL level; accordingly, it has a wide dynamic range. This new version features five switchable polar patterns and built-in LEDs that provide a quick visual indication of the polar pattern that is selected, and also an overload indication.
Neumann is well known for its famous and historical line of condenser mics, but I want to mention one that perhaps you haven't seen or heard yet: the KMS 105. This is a condenser mic without a large diaphragm, but with the special features of a hand-held performance mic. If you have jocks that like to grab the mic and move it and the boom around while talking then this should be of interest to you. It has a tight polar pattern, thus minimizing pickup from the rear of the mic. It is optimized for the vocal range of frequencies and finally it has an integral four-layer pop filter built in.