I think it's best to get your sound quality sounding the best you can without resorting to a lot of plugins on the Master. But I do like PSP Vintage Warmer, URS Strip, Waves API 2500, Voxengo Elephant, WaveArts TrackPlug, PSP sQuad, Voxengo Analogflux Suite. I like to use CLAS also which is like a BBE Sonic Maximiser module, but better sounding IMHO. I personally like to use these plugins at subtle settings, especially if on the master. Their just to add some more presence and tighten everything up nicely. BTW, I don't use all those plugins at once, just depends.