I do not use reason so I can't help there, but I am an avid ableton user so I will try to give you some tips that I have learned over the last couple years.

Get a couple really good VST synths. NI Massive and Camel Audio Alchemy are two of my current fav's. They have a LOT of great sounding presets that you can use to start your idea and get going.

Secondly, there are a lot of different types of bassline's used in prog house/trance music. I guess it depends what type of sound you are going for exactly. Producers like Deadmau5 and eric prydz (pryda) both use a pumping sidechain bassline quite frequently, and others use more of an electro sounding, groovy sequenced bassline.

Try using multiple octaves and bouncing on the same note up and down an octave. Also, when you get a good sequence that you like, duplicate it on another bassline instance and give it a slightly different sound (perhaps taking the sequence down or up a full octave so its using a wider range of notes). Using the great FX that are built into ableton is also key. Ping Pong delay with no feedback and flanger can really improve your sounds.

If you have any more specific questions in regards to making a bassline I would be happy to answer them if I can, your question was pretty broad.

http://www.youtube.com/watch?v=mKUb9Txoe1c - check out this short video showing an 8 minute screencast of a producer creating an electro sounding track in ableton. Watch what he does when creating his bassline sequence to get some tips :)