The biggest difference between the hybrid bikes (Trek 7200) and the comfort bikes (Trek Navigator) is that hybrid bikes use a 700c rim with tires around 35mm in width, a comfort bike uses a 26" rim with tires between 1.75" and 2.2" wide. 26" wheels are used on mountain bikes and 700c wheels are used on road and cyclocross bikes. At this level of bike there is not really a reason to go with one over the other.
Some general thoughts:
I really do not like suspension on a road bike. Its heavy, complex, unnecessary and power robbing.
Both types of bikes listed are fairly upright. Even more upright with a lower seat height is a crank forward design like an Electra Townie or Trek Pure (Sole Ride in 2006 models).
Nearly every manufacturer makes bikes similar to these. Smaller brands may offer slightly more for the money but your best value is probably to find last years model on sale.
If you are new to cycling or are not mechanically inclined it is best to find a local bike shop (LBS) you are comfortable with. Its easier if they are close but sometimes a good shop is worth the distance.
Craig