Steinberg Tube Compressor - It just makes everything sound better. I try to max it out at -2dB compression with Auto "on".
Steinberg Multiband Compressor - I use only the mid-high and high bands, adding about 2dB of the mid-highs and about 3.5dB to the highs.
Notice that the output is set to -6 to reduce chance of overload in the chain.
Next goes "Character" from Noveltec/Plugin Alliance. Just to add a bit of presence ... sprinkle in as needed.
Of all the tape emulation plugins, I find Magneto from Steinberg to sound the best.
Last and possibly most importantly, I put Steinberg's limiter in the chain. With it set to Auto Release, I will balance the levels, making sure not to over limit (usually 2dB and rarely more than -3dB of GR).
For my mixes, I will often add a bit (1 - 1.5dB) at the low-end (100 or 160Hz). At the top I'll add from .5 to 2dB at 2600Hz.