I had a Raleigh for a long time (8 or 9 years I think), my sister had a Trek for equally long and rode it all through school, and my mom had a Canondale. All of us used to ride around on them pretty often (few days a week) but my sister was the only one who ever really got into doing distance rides. Most bikes last pretty long if you take care of them, so long as you don't just go to Walmart (or Target or whatever else) and pick one of the shelf cause it's pretty
. Shop like you would a car-- more expensive isn't always better but too cheap and you get what you paid for.
One thing to watch out for with the less "sport" bikes is skinny tires. Every bad accident I ever had on a bike was on one with thin tires instead of the thick kind on road/mountain bikes. Almost died when the stupid thing got stuck in a grate once at the bottom of a hill and tipped the bike over, me first over the handlebars then the bike on top of me.
Also, there are seat cushion add-ons you can buy pretty much anywhere that just slip over top of your basic saddle. If you aren't planning on any serious biking you might want to start with something like that.
As for safety-- I live on a street that desperately needs two things: A bike lane, and riders who know how to ride a bike. Most drivers are willing (at least grudgingly) to share the road on one like this with a lot of stop lights, low speed limit, etc. There are lots of bicyclists here, and I'd say less than half of them realize they're supposed to follow the same laws as the cars. They'll zoom along on the street, then when a light turns red, they either just straight run it or cut over to the sidewalk, knock over pedestrians, cross , cut back into the street, and almost cause about 5 accidents.
I have had a few friends/coworkers hit by cars while on their bikes, and 9 times out of 10 it's their own fault. Ask them how it happened, and usually they were running a red light or a stop sign or turning left in front of someone. I don't know if it's just this city, but people need licenses or something. The people on the sidewalks just run you over with no warning that they're coming up behind you.