In the box - that would be LP MB. It is fairly surgical, and musical. The next up is Sonitus, because it works really well on side chain bass track stuff and it’s easy to dial in.

If you want to try something that “makes” you think out-of-the-box, try the Kush Audio VSTs. I recommend the UBK-1 for compression. After you get the hang of it, you’ll wonder how you ever got along without it.

I have used the Sonitus multiband on a lot of 2 trk live sound recordings for taming bass and whatever it is doing to make the upper end sound really nice.  
 
And the CA-2A for individual instruments.

I've used the PC ones a lot - 76 and 2A - and I do think they're good. I've been using Reaper more lately, so the VST version of the 2A is nice to have. I *love* Supercharger GT. Just picked up the IK black 76 for "free" (well, the price of a CM digital issue) and you can too if you want - it seems pretty good! I also have used their Fairchild a lot on the master bus, and sometimes the Opto one as well. Also recently grabbed the Hornet multi-comp, which is pretty cool - lets you try a few flavours out and compare them very quickly. I've also got the Ozone and Neutron component plugs which sometimes fit the bill.

But since Waves released the Scheps Omni Channel I've been using it more and more - 3 flavours of superb and remarkably full-featured compression in a highly configurable channel strip format, with equally sophisticated saturation, gate, EQ, de-esser on steroids, and the possibility to lay in another instance of any of them, like for example a different flavour of compression, anywhere else in the chain. Or any other Waves plugin you might like to add. It's just a monster. A channel strip with all the control of individual plugs, including wet-dry and M/S per section. Did I mention it sounds amazing? It's kind of hard to find good reasons not to use it on everything.

My new fave is the API 2500 from Waves.  I've never owned the hardware but this plugin does some nice stuff to  pretty much anything you put it on.  I scarfed it up at one of their $29 sales.  Next would be the CA 2A from Cakewalk.  As for multiband compressors- the Waves C6, LMB, and L3 Multimaximizer get used a lot. 

1. Pro-C2, because it's versatile and precise
2. CA2A, because it's easy to use and great on vocals
3. Kotelnikov, for gentle bus compression
4. Sonitus, because it's easy to dial in a sidechain
5. MJUC, because it's a good compromise between ease of use, nice algorithms and versatility
 

Here's my lineup, FYI.  Main reasons for use, sounds good to me.
 
Bass - PC4K S-Type Channel Compressor, smooth.
Drums - PC76 U-Type Channel Compressor, parallel comp
Mix/Master - Adaptive Limiter, easy to use.
Mix/Master - L-Phase Multiband, great detail.

CLA-2A, CLA-76 and MJUC on individual inserts. 
Waves SSL G-Master on busses.
They usually get me there. 

1.) I level out vocals with Melodyne and then I use a bit compression with the CA-2A, because it's best in leveling IMHO.
2.) PC76: Easy to use and like the fast access in ProChannel, especially when switching between tracks, like its use on guitars and sometimes for light compression on synths or classic instruments
3.) Kotelnikov (free), TB_Compressor and TB_BusCompressor: I like their interfaces, because I prefer to set the values with the mwheel & shift mwheel (they are very precise, best IMO), and they are subtle and don't change color

Another vote for CA 2A on vocals especially. The new Scheps Omni compressor component is also really nice on almost anything I find.