What is the logistical difference between side-chaining a compressor through an equalizer to compress only certain frequencies versus just applying a multiband compressor affecting the same frequencies? (for instance when tracking vocals)

This question arose from Dallan Beck's book The Musician's Guide to Recording Vocals

What are your favorite of each, for maybe around $100 each? I don't have a problem with Behringer and I don't want to go too crazy especially because I'll be having this in my dorm room.

I already have -> Firepod, SM57, and AT2020 for microphones. I want just one more mic and a vocal compressor so I can play + sing at the same time and have a more leveled out vocal track.

I would like to find a nice warm compressor to use for vocals, but also one with a de-esser so I don't have to multi-band that out in post. Is that something that is usually combined? Or is that something that needs to be a separate piece of equipment?

If I get a multi-band compressor, does it still have an overall compressor that is not band-specific?

Whats youre opinion on a comp for acoustic guitar/vocals at about the 2g range?

Of the compressors available today, what would you recommend, with the assumption that it would be used mostly for vocals? I've been narrowing things down a bit, and here's what looks good:

UA 1176N
UREI LA2, LA3 or LA4
Empirical Labs Distressor
dbx 160S or 160SL
Manley EL OP (or, really, and of their comps)
Purple Audio MC77
Drawmer 1968

Heres my simple setup...

U87 to Avalon 737 to (undetermined compressor) to Apogee Rossetta 200 to Apogee X Firewire Soundcard to Nuendo (PC).

I produce R&B tracks for an independent label here in the UK - since I can remember there's been a lot of respect for the US vocal sound (and US production in general) - a lot has to do with the quality/character of the artist, but I believe the mice/compressor has a lot to do with it too. So what compressor?

I've heard of a lot of people doing this...
what are the benefits

I've heard that some guys use 2 Comps while Vocal recordings.Your opinion? (or any good set ups?)

Here is an email question I received from a friendly reader of the RO forums. Before I give my opinion, I think it would be helpful for him to hear some other opinions as well. Anyone want to chime in here and help him out?

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Hi Jon,