I do like to add the LP64 Multiband (as well as the LP64 Equaliser) soon after I have a rough mix. I mix into these as it gives my mastering engineer an idea of what I may (or may not), wish to achieve. I'll remove it before sending off to be mastered, but send a bounce with these plugins on the track on so he can get an idea of what I was hearing while mixing.
I have recently purchased the Melda Dynamic EQ plugin, as I've seen some good reports about what I may be able to achieve with this, and am getting some (subjectively) nice things happening.
I believe the more things about the track I can communicate to the mastering engineer, about what I want the final track to sound like, the less chance there is of getting back something I'm not happy with.
I don't see the point of leaving the LP64's on the track that I want mastered, as the mastering room has some awesome effects that I don't seem to be able to replicate on my DAW, and I do like to leave the final compression and EQ to a fresh (and possibly better trained) pair of ears and a better sounding room.

This

http://cdn-downloads.tcel.../media/1120849/md3.jpg

and this

http://cdn-downloads.tcel.../brickwall_limiter.jpg

Perfect with jbridge and Platinum 64 Bit

The ol' LP-64 is pretty darn good, but the ol' Ozone 6 VST plugin is another level.. :O)

Could one use the Tone2 BiFilter2 as an exciter/maximizer.  Set it up on a send bus with a bandpass filter and some saturation set completely wet?  Then add a second instance, to filter out the initial signal (after bandpass).  Allowing just the distortion harmonics.  Fine tune to taste.  Just a thought...

Interesting idea, but I suspect it'd be in the area of using an axe when you need a scalpel. The bifilter excels at really extreme resonances and steep cut offs. Good multi-banding is a bit more nuanced, I think.

No multi-band, no comp at all on the master buss.  Seldom anyway.  Or if I have an SSL - the hardware not an emulation.
 
@

I use the built in Samplitude Pro X multi-band compressor followed by a Waves L2 limiter for mastering, works for me!

Ozone 6 for sure BUT only if you know what you're doing. It can do so much and very quickly wreck a mix

mudgel
Ozone 6 for sure BUT only if you know what you're doing. It can do so much and very quickly wreck a mix

That's pretty much true of anything you put on the master bus. 
 
One of the best thing about multiband compressors is you can think of them as graphic EQs where you can choose to compress particular bands.
 
As to whether to use/not to use, it's pretty much a case-by-case basis. If you're mastering your own material, you can always tweak the mix so the mastering requires a lighter hand. If you're given a two-track mix, all bets are off as to what needs to be done.
 
The main element I like about maximizers is how they bring up lower-level material, like ambience. With programs like Ozone or Wavelab that can level-balance the bypassed/enabled status, you'll often hear no apparent difference (or at least hopefully you won't because the maximization is minimal) except for quieter passages. I've found a good ballpark figure is about 4 dB of reduction, i.e., after the entire song has played through, check the meter that shows the maximum amount of reduction that occurred. If you have someone who wants to win the loudness wars, you can push it to 6 dB without causing too much damage; for something like a jazz tune, 2 dB will give a nice little lift and be unobtrusive.
 
But of course, it all depends on the material. With classical music productions, I lower the gain manually on a few peak half-cycles to allow bringing up the level a tiny bit without any artifacts.

I use the Fab Filter Pro-L limiter as well as the Pro channel EQ on the master bus.