Headline fonts are a different matter. Here, you should look for shape rather than line length. Impact makes a striking, if slightly clunky, headline font. The only trouble with this is that there’s no alternative that’s even close, so use with care. Charcoal (Mac OS 9 and Classic) and Charcoal CY (native Mac OS X) are inherently bold, but not as narrow. The nearest Ubuntu Linux equivalent is Baekmuk Headline, not a particularly well-made font but at least it has the weight.
Script fonts are harder to pick. The humble Script in Windows is the only option, and this isn’t smoothed on screen. On the Mac side, Lucida Handwriting is fairly casual, Edwardian Script ITC and Bickham Script Pro are ornate options, and Handwriting - Dakota is a very casual choice. Ubuntu Linux offers the casual Purisa.
For the adventurous, try Copperplate, Copperplate Gothic Bold, Gill Sans, Gadget, Arial Black. Where this works, it looks stunning. Where it doesn’t, Arial Black gets the message across.