i personally base my flight routes on payware airport addons, in the past year i bought around 20 airports accross europe like EDDF, LKGOS, LPFR, DTMB etc.

My main hub is EDDF and from their i created some routes towards all my other payware airport destinations with a self painted CS727 and CS707 (all cargo flights) depending on airport size :)

I have combined it with a small program FSCaptain (like fspassengers) to give a bit more touch :)

currently i'm saving some money to expand AES to get more live on the airports based around my aircraft (get a follow car after landing and stuff) very neat.  8-)