late to this by a bit, but there was no closure at the end of this post!  Or did I miss it?
Vibe is pretty light for a car this size, so about the only thing you can really do is to find the softest riding tire out there.  The 
Goodyear Assurance "ComforTred" is highly rated for comfort.  TireRack survey results put the 
Pirelli Cinturato P7 All Season Plus at #1 in comfort, along with very high ratings for everything else, so probably it's expensive, but not sure, I haven't looked this tire up.  The 
Continental Pure Contact Eco Plus was rated at #2.  The
 ComforTred came in #5 on that list. There's a total of 32 tires on this list.  
	
Something to note about this kind of soft riding tire... their side walls are generally quite soft, so they will tend to respond a tad slower than a sporty stiffer sidewalled tire. 
I never saw what tire pressure you keep your tires inflated at, either.  Tire pressure does affect how the tire responds and how it feels on the road.  Higher pressure tends to firm up response, increase road feel and feed back.   
You should 
never go below the Car Manufacturer's recommended tire pressure... and
 never over inflate a tire beyond the cold 
Max Pressure number on the tire.  I try to check tire pressure every 2 weeks (cold, tire sitting overnight), and anytime the temperature cools or heats up a lot... over 15 to 20 degrees in either direction, since for every 10 degrees of temperature change pressure in a tire will change by 1 psi.  When temperatures go down, tire pressures go down.  When temperatures warm up, tire pressure moves up. Tires lose about 1 psi per month on average, no matter what the temperatures are doing.   
   
The Continental Pure Contact Eco tire is highly rated.  For an All Season tire it has very good grip ratings in snow as well, including low rolling resistance benefits.  A friend of mine just mounted a new set of these tires on his car, so I'll be gathering some first hand impressions on that tire this Winter.      
Here's most of the TireRack Survey results list... I had to make it small to grab most of it.  You can download it and zoom in to see it better.  
