ThunderPoit, that looks like a great cruising/commuting bike. Specialized has a wonderful reputation. Looking at the photo of your bike, I just see one of those stylish, sleek and contemporary brushed-stainless steel... what to call them? beverage containers. I guess you can't properly call them water bottles. And of course you'll need an equally cool cage.
Colorado Cyclist is a good mail order resource for cycling accessories -- including helmets. Have you purchased a helmet yet? Also,
REI is good. I've had excellent experiences with both.
Yes, a cycling computer will add another dimension to your rides: at least, it'll help you
measure and meaningfully improve your rides. Decent cycling computers are inexpensive, and their installation requires just a little fiddling with small wires, nylon ties and precisely-placed magnets. I recommend a computer which includes cadence.
Finally, as a general suggestion and resource for all cycling enthusiasts,
Sheldon Brown is a man who writes passionately -- if not a little idiosyncratically -- about cycling... and the
idea of cycling.