I’ve used ThickBox on 2 different sites so far one of which is a MODx run site.
A breeze to implement. I quite like jsQuery.
On one of the sites it’s used to display a summary of pdf documents before people download it. I’ve had very good reactions from people especially for this use because they can make a better judgement before downloading huge pdf files. You can see it here:
http://www.rivers.gov.au/lww/toc_rain.htm (and no the design is not mine, no not a modx site and yes the html needs recoding)
The only time I am having a problem is when I’m logged into the manager and view the site (that’s teh other site

). For some reason quickedit causes a problem with css transparency in Internet Explorer so when a thinkbox pops up the background goes black instead of a transparent dark grey. Not a big problem though, who cares what I see, what others see is more important
I just plonked the necessary bits into a template, adjusted a few paths and set some classes. Worked first time.