...

First, open your browser and enter "about:config" as the URL. This will access Firefox's
internal settings. Click through the "please be careful" warning, then simply change the following:1.

Enable HTTP Pipelining

I did some research as to why this isn't enabled by default and really couldn't find any good reasons.
Apache Traffic Server supports this, and I got a roughly 100% speed boost by enabling it.
I also dropped the folks at Mozilla a line and suggested they support this.

...

NOTE: As much as you'd like to enable "network.http.pipelining" specifically, it is unfortunately buggy.
I'm guessing this exposes internal bug(s) within Firefox, but if that setting is enabled images from both
Facebook and Twitter start to go missing. Bummer.2.

Increase Proxy Connections

As it turns out, this setting is artifically low on the presumption you'll be using a public proxy
on the Internet and that it's "bad etiquette" to send such a server too many connections.
Being that I'm not going to kick myself off my own proxy server, I went ahead and changed this.

...

That's it. Go ahead and restart your browser just to be safe, then enjoy your increased surfing speeds.

Epilogue And Ongoing Problems

Well, that's it!

At this point I believe I've resolved any lingering problems, but of course only time will tell.