Will WinAmp populate the tags if they start out blank? Or just correct some missing tags if the artist and track name are already pre-filled? Or I suppose it can work with artist and album name and then track times to figure out the track names.

Is it producing track labels that you're satisfied with? I generally have to make manual edits to all data sources because so many people use different conventions. Even when a convention has been standardized, such as at RateYourMusic.com, it's not necessarily something I agree with.

For instance, braces () only appear in my song titles if they're part of the title. All Remix attributes and credits always go in square braces [] at the end of the title. Such as "This is the Song Name [Groovy Remix]"

Guest artists or duets always get listed with the artist and not as part of the title. I then use the BAND (aka Album Artist) tag to store the name of the artist for the album (for non compilation albums). So I'll have a song by "David Bowie and Mick Jagger" or maybe "David Bowie feat. Placebo" for example.

For artwork I would first start out with iTunes. Let it download art for whatever it can. It will store this in files on your drive, not within the tunes. Then use a third-party program to imbed the images into the tunes. When you're done, then use whatever other solutions you want for the tracks that still lack art.

I suggest this because iTunes seems to always have higher resolution/quality art than sources used by these other programs (most of them rely on Amazon, AMG, etc..)