+1 for the L3-16. The ability to prioritize frequencies above others is amazing. For example, in Mastering one thing that is extremely tricky is to retain a bit up "bump" and punch from the kick drum, meanwhile not over-taking the vocals to do it. Here, I can prioritize the vocals, but de-prioritize the cymbals, and bass frequencies. Then I use a precise Release time and character to poke the kick through without being obtrusive or too pumping in the mix. Couple this with a great EQ and Compressor (placed before the L3-16), and we're quickly making great masters!

UAD SSL - Use it all the time and haven;t found a better sounding final mix compressor and I have many including others by UAD, Waves and of course Cakewalk.  It does the job without coloring the sound too much and is as transparent as you want it to be while still pulling the mix together.  Also, I use the UAD Ampex 102 along with it which really works great!

I did a little work with the Concrete Limiter and..... it's not bad. Lacks a bit of clarity, to me. A little bit muddy.
Also downloaded the Limiter no. 06 by Vladg. Haven't had much time with it but, so far, it sounds pretty good.
My benchmark is the Sonnox Oxford Limiter. I love it. I would just buy it and be done with it if not for the iLok thing. I've just never wanted to get into that.
Still searching.

no iLok for Fabfilter Pro-L and free trial available

Thanks, scook. I'll check it out.

Over the years I've tried to be disciplined about maintaining levels such that a limiter set at -0.1 would be redundant.  I quite like the idea of setting a limiter this way, but more and more I am trying to manage the gain staging across the signal path from track to bus (to bus...) to the master out so that the levels are somewhat consistent across projects as well as within them.

Usually I have either Ozone 5 or the Concrete Limiter or Waves L1 or even Boost 11 on the master bus, but I have these set to disabled while mixing.  At some point I'll enable these just to get a sense of their effect, either in terms of assessing various loudness possibilities or as an experiment for the learning/fun of it.  

The cool thing about running your own studio for your purposes is doing things that match your workflow, regardless of whether they would be acceptable by the public at large.  I think the closer you get towards mastering, the more the accepted ways might be the preferred or arguably "better" ways, and in that case I'd lean towards what are accepted practices in the professional world of mastering.  Sitting in on such a mastering session, as someone suggested, is a great exercise and learning experience.

I never purchased the Concrete Limiter...but I do have Sony Vegas Pro which has their Wave Hammer.  It works really well for me.

I don't think you could go wrong with T-racks or Ozone 5. Both are very good. Fab Filter is very pretty! and it sounds great. Limiter No.6 is the best free limiter I've found.

Just thought I'd add - It's good practice to set the limiter ceiling to "-0.3".

the boost 11 that ships with Sonar I think is great.
does what is says and no more (no 'side effects' you dont want like with some other limiters).