Is it bad to hotlink jQuery from jquery.com?

Better hotlink it from Google API libraries.

Very big advantages:

• Google is fast and highly available
• Separate hosts, allows the client to load JQuery simultaneously with your pages and images (browsers support only a limited number of connections per host)
• Probably even faster still, because many websites use it, so this Google version is probably in your visitor's cache anyway.

Are you using their official CDNs? (old link) A lot of people do.

I'm not sure why everyone is so quick to say Google. The above link says very specifically that you can hotlink to the jQuery CDN:

jQuery CDN (via Media Temple)

http://code.jquery.com/jquery-1.6.1.min.js Minified version

http://code.jquery.com/jquery-1.6.1.js Source version

Instead use Google's CDN. That is what it was designed for.