If you're mixing digitally, just use the meters in the host program. Don't even give a thought to the RMS level - That's how people mess up their mixes.
You don't want to clip, and many M.E.'s (including myself) appreciate 3-6dB of headroom to mess with. In 24-bit, you're never going to miss it, but you'll certainly regret it if the mix is clipped or otherwise limited.
That all being said, I'm sure that some names of plugs will be thrown around... Just try not to rely on them too much... Ears, not eyes. 8-)