When recording vocals, nothing you put on the track in the way of a plug in is actually doing anything to the audio file. So, its best just to get a level which is as hot as possible without clipping.
If you have an external limiter/compressor you might want to slightly limit the vocal just to smooth out any nasty transients. Once you get a nice even vocal burned then you can add effects as needed.
If you have the horsepower in your computer a nice reverb just to help the singer along might be in order.
Using EQ or Compression plugins can mislead your levels and you could end up with some overs, I would not reccomend it.
After you have your vocal recorded I would set up an EQ to rolloff the lo end and then either a track or buss compressor to warm it up a bit and give it that radio sound.
Hope that helps.
MM