@chrishajer: I am putting Twitter updates in a subsection of the footer area that is only shown on the home page. Since the overall subsection display is already being controlled by CSS, I don’t need to have widget-level display control, e.g. Widget Logic.
But as I mentioned above, the JavaScript would still load on every page – so I put a routine in my functions file to only load the JavaScript lines if the user was on the home page. Maybe Widget Logic would lead to same result, but I’m using a variety of custom page templates and have a lot of manual “widget” areas using hardcoded template tags and custom functions, so it was relatively trivial to handcode it. This is all in a child theme of the Thematic framework.
Since none of the non-Javascript Twitter plugins have been working, I’ve actually just gone ahead and used Twitter’s HTML/Javascript badge code right on the website – HTML in a text widget, JavaScript in the functions file. Not much control over the display elements, but at least it consistently works for my client.