What plugins or effects do you find yourself coming back to time and again? Or any specific efx chains that help define your sound?
For reverb, especially vocals, after trying out tons of plugs and hunting through tons of impulse files I find myself coming back to Fokke van Saane's, Master Room MR-II, 3 MR-II (Brilliance 50%), impulse file with Fruity's Convolver. It isn't the widest reverb, but it is an actual stereo spring reverb and the Convolver allows to adjust the wet stereo separation. Its about the closest I've come to that early 80s / late 70s style reverb that I'm after. Though Fokke van Saane's Lexicon 200 impuse files are really good too, but have more low end so need a little filtering.
For compression on instrument / vocal tracks when I need a little bit extra, I seem to always fall back on the Waves LA2A, but I'm also really impressed by Softubes FET Compressor. Softubes CL-1B is really great, but the level / make up gain knob seems a little wonky. I find if I adjust the compression then turn up the gain (makeup) I have to go back and tweak the compression settings again, since the pumping seems to change.
On snare I keep coming back to the Waves API550b, sounds great on toms too. Just don't forget to turn off the analog noise switch, or else your mix will be full of hiss BS.
Using tape or a tape emulator as a limiter is a big part of my master buss sound. The natural dynamics of tape was a huge part of the 70s / 80s sound so I feel personally that you can't really get an authentic synthpop / disco sound without hitting tape at least once in your process. Its pretty difficult to find a decent real tape machine thats in good order let alone tape to use in good condition. So I've been using the Waves Kramer Master Tape plugin which gets pretty damn close. Although one thing thats kinda cool about tape, like tube amps, is each deck is a little different tonally.
I've tried using cassette based recorders, but I've always run into problems with jitter / speed distortions. But if your making one shot samples, like for example drums or bass guitar, something your going to chop up anyway, then you can definitely get that compression / tone by hitting a hifi cassette deck then recording it in and making sample patches. I did that with my Pbass and it turned out pretty good.