Those are two different animals; the DB is a "comfort" hybrid whereas the Schwinn is a "performance" hybrid. (Disclaimer: These are my terms to describe these bikes, not industry standard.) The DB has a more upright seating position and the Schwinn a more aggressive one. Based on components alone I would choose the Schwinn hands down: Altus 8-speed rear derailleur vs. Tourney 7-speed, rapid-fire shifters vs. twist-grip, rigid seatpost vs. performance-robbing suspension seatpost, etc. IMHO the Schwinn just looks better, too. Lastly the coolness factor of that YouTube video on the Schwinn leaves the DB in the dust.

If this is your first bike and you're on a tight budget you could also consider a CL bike; look for an early-90's rigid (no suspension) MTB. You can usually find one for less than $100. Take it to your LBS for a tune-up, slap on some slick tires and lights and away you go. Add a rack and fenders and you got yourself an all-weather, all-purpose commuter, likely for less than $200 all told. Ride it long enough to save the money for the bike you really want. BTW - take a friend who knows about bikes with you if you do decide to go used.

Something like this bike in Toronto (check CL in your area; this only took me a minute to find). http://toronto.en.craigslist.ca/tor/bik/1854022809.html

If possible stick with a well-known quality brand like Giant, Trek, Specialized, etc. Same goes for new bikes; both Diamondback and Schwinn make bikes with cheaper components for dept. stores (sadly, like your two examples). That's why I suggest going used, saving your money, and then heading to your LBS with wad of cash in hand when ready!