For UA metal flights within a reasonable drive you've really only got EWR, BWI, and ABE. Anything outside that approaches 2 hours in good driving conditions from PHL (LGA, IAD, MDT, and JFK are too far for me anyway...). As others do, I check these airports when I'm looking to save a few $$$ and they rarely beat UA's prices out of PHL.

Having used PHL extensively for almost 20 years I suppose I've become hardened to all of its faults. I've also developed a ton of tricks and coping skills . You've found one of the best ones in bypassing the kettles clogging the D screening line though that one might be fixed when they open the new combined D & E screening area (in 2009?). Of course, it might also get worse...