Master Bus or Mastering chain within Sonar Plat

I don't have a standard mastering chain, other than SPAN is always at the end of it. 
 
Looking back at my last 3 projects, each one's a little different:
 
MSpectralDynamics -> Ozone  -> Pro-L -> SPAN
 
Ozone -> SPAN
 
TDR Kotelnikov -> Pro-Q -> Pro-L -> SPAN
 
One reason they're different is that Ozone contains multiple modules that may or may not be used. For example, I might use MDynamicEQ in place of Ozone's Dynamics module, Pro-Q instead of Ozone's EQ, and Pro-L instead of Ozone's Maximizer.
 
What they tend to have in common is some kind of compression going into an EQ into a limiter, and SPAN at the end as a sanity check on the whole thing. The compressor might be broadband, multi-band or a dynamic equalizer, or none at all. The EQ is typically very subtle, and more for widening than correction. Choice of limiter is made after auditioning both Ozone and Pro-L and seeing which sounds better - I use them about 50:50.

It's fascinating when you think about it, but often when reading an album or EP, there are a few tracks that just end up sounding sweeter, warmer, punchier than the rest. Hard to describe. I've tried applying the same mix and mastering settings to duplicate the effect, but there are too many variables. The performances, the Dynamics, the key of the song, the instrumentation are all a little different. A client once told me that he thought that mixing would be like following a recipe book and that he gave it a go. He quickly realized that you can't simply follow prescribed steps. He gave up and again pays professionals to mix.

My typical (plug-ins ~ in-the-box) chain goes like this (Assuming for CD or online distribution or airplay)

NOTE! All of this is subject to whim, the project and general trying things. Don't not try things! You'll surprise yourself. Take good notes.

• Hi-Low Linear-Phase pass EQ filter with sharp roll-offs on the high and low end where super high or low frequency information may be present, but useless. My favorite for this is the DMG Equilibrium, since is has a wonderful sharp roll-off. You don't need the -18db rolloff I use, but it helps me keep all the low-end I want.
• Linear-Phase M/S or Stereo EQ for notching, filtering, correcting. Again, my go to is DMG, but I may use EQuality which is a little easier to work in for me, unless I need a specific type of EQ boost or notch. Waves just dropped their new Dynamic EQ, which is perfect for this, and I'm beginning to use it a lot. Quite inexpensive for the power! Previously, I used Sonalksis CQ1 and DQ1 for dynamic problem-solving.

• General compression (analog modeled). The 4K type is really good. I typically use Waves SSL 4000 Buss Compression, the API 2250, or other great buss compressors. I leave about 10-30ms attack clamping to help retain transients

• If there's any issues I need to address with a compressor/ducker/expander, I'll use the Flux Alchemist, which is a phenomenal plug-in, but if used because using it is cool, it can quickly get you into trouble. It's not always a good plug-in for overall general use, but excellent at addressing individual issues because of the incredible power it has. If I don't need it's power, but still want to use Multiband compression, I may reach for a Linear-Phase MCompressor. Waves makes a great one, and I understand now CW has a great one.

• Next, I'll use a light full-range slow compressor for overall taste, such as an LA-2A type (used lightly in opto mode), which just adds a bit of presence and pleasant fullness/glue to the song.

• Moving on, I try not to use more than one limiter, if my compression is good. However, I do really like the Waves L3-16 for limiting. I may opt to use a very light limiter first to merely address some peaks/overs, but not always. The Waves L3-16 is excellent in that it has a Priority function. This allows you to tailor the limiter to prioritize transients in a frequency range over other frequencies to taste. I can dial in the right amount of kick-drum punch without drowning out cymbals.

• To finalize, if I'm going to CD I've been having success with the Kazrog K-Klip Pro 2. It does a fabulous job of useful clipping for those darned loudness wars. I may use this before or after the L3-16, just depends. If I use it before, I'll use the IDR sample-rate/bit-rate conversion in the L3-16. If I use it after, I'll use Sonar or Wavelab's down-sampling. Don't forget to dither!

• If I'm going to deliver for online distro, I'll use the Nugen ISLst in front of the down-sampling to ensure I'll have no after-the-fact digital conversion overs.
• Finally, metering. I'll use a cool product called Meterplugs Dynameter for PLR dynamics measurement, Nugen Audio Master-Check for target loudness, Brainworx bx_meter for overall metering, and Flux (free) Stereo Tool for overall phase correlation, if not using Waves PAZ Analyzer, or the meters available in Wavelab Pro. At times, I'll use Magic AB 2 to compare my results with the industry. Wonderful tool!

• There are sometimes Convolution Reverb or Stereo field widening/narrowing, etc. I may deploy for some things, such as narrowing the bottom end for vinyl mastering. I use the Nugen Monofilter for that. I like East/West QL-Spaces (I don't own the expensive Altiverb, although I've salivated over it) for convolution reverb.

With all that said, the plug-ins I use are always optional, and there's some great (free for Sonar Plat users) plug-ins that will also do a fabulous job! Don't sweat the brands. Sweat your room, monitoring, and your own skills. That's where it counts most!

The main message to take away is that there's no "best" solution. Everybody's got their own way of doing it, and many of us have more than one. Rather than noting every recommendation here and buying them all, your best bet is to settle on a small selection of tools and then proceed to learn each of them inside and out.
 
If you want to do it on the cheap, this would be my recommendation:
Kotelnikov -> Cakewalk LP-EQ -> Cakewalk Adaptive Limiter -> SPAN
 

I have a lot of relatives who like bok choy. Small world. 

oops. Double post due to browser lag/freeze.

BTW each month in the Tech+Music magazine I do a column called "You Mix, We Master" that describes the process of mastering a reader-submitted piece of music mixed in SONAR.