From what people have been saying, I think I'll probably stick with a hybrid rather than going for the comfort bike ride. Even just going around parking lots I can tell a definite difference in the speed between comparable comfort and hybrid bikes, so if I'm doing a longer distance, I can see where that might be frustrating. (Or if I'm having to huff and puff to keep up with other riders because of my bike's ineffeciencies.) By the way, thank you CTYankee and Chephy for the answer and question as to why Chephy wouldn't want to do 10 miles on a comfort bike.
At the same time, however, I really like the upright stance and the cushy seat (it's one of the reasons I didn't ride my old bike as much as I got older). If I was in it purely for the exercise, then I could get a gym membership and use an exercise bike. I want to be gazing about, looking at the world, and the hunched over postures really won't help with that. Plus as I said earlier, I'm not into really fast speeds. If I'm on a weekend ride, it will probably be pretty leisurely along the river going to look at different plantations or something like that. One perk about Louisiana for bikers is that it's pretty much flat as a pancake, so unless there's a highway highrise, there are no hills.
Even so, I doubt I'd use more than the 21 speeds available on these bikes.
Of the bikes that have been mentioned, I'm definitely going to check out the Cypress. Is there a minimum model level I should be looking at? And do you rank it above the Trek and the Raleigh? Though I definitely appreciate the other suggestions people have been making I want to be able to try the bike out and the brands that are carried locally are:
SE Bikes
Fuji
Pinarella
Kona
Kuota
Guru
Raleigh
Kestrel
Giant
Trek
Cannondale
Serocca
Gary Fisher
Orbea
(Kona Smoke is out of my price range.)
Thanks for your suggestions, and keep the recommendations coming!