The 2.0 is an 'old tech' 8v engine and although it has less power than the 1.8T the fuel consumption is actually higher. Not to mention they drink oil for a hobby. Reliability wise the 1.8T is very reliable, certainly the mechanicals are rock solid, the common problems with them are generally the sensors (air mass, O2, temp sensor) most are very easy to sort yourself if you know which one's busted (this forum is a great help with that) and you will probably get a few more bells and whistles on the turbo model than the 2.0.
If modding is your game you can very easily take a 1.8T up to 200bhp for relatively little money while getting any significant performace gains out of the 2.0 will be difficult / expensive.
Insurance wise the 1.8T will be a little bit more expensive, depending on your age I suppose this could be a major decider!
Appols to the 2.0 owners, don't mean to diss your rides, both great cars and you won't be dissapointed either way