I have a few rack things that are "must have's" for me. Most are either homemade like my mixer or expensive, like my Summit tube eq and compressors. I have an old Yamaha SPX1000 reverb that sounds good to me, better than any plug ins I have.
The only cheap crap I use is a pair of Boss compressors that sound good to me.
Here's my basic lead "anything" trick, from one of my favorite producers, David Foster:
I take the lead vocal track out from the computer and put it through the Summit passive tube eq and crank the shit out of the treble, then put it through a compressor (in my case the cheap Boss) to squash that treble peak down. What it does is "adds a glaze" to the whole track, so there's this "AAAHHHH" sound on the vocals. It makes the vocals stand out, adds a shine. The sound I'm looking for is the same as when you see a Walt Disney cartoon and Bambi is stuck right on top of the background, if that makes sense. It's important to me that the vocals, or lead whatever, have more "shine" than the cymbals or anything else, or it makes "Bambi" blur into the background.
I started as a cartoonist... it could be that no one affected me more than Walt Disney, he's got to be the top producer of my lifetime.