...hmmm...well you don't tell us what kind of music you want to master
I usually use Wavelab - as for the plug-ins I would probably choose waves over U-Audio...but that is a matter of taste. If you want more coloration then go with U-Audio - Waves seems to me a bit more precise.
As for T-Racks - well that works too of course. But in WaveLab you have better functions for Mastering purposes...