For returning bike-riders, my sanity check list:

1. You don't need spandex or logoed jerseys, yes...they do look rediculous, and yes...those teenages you passed on the corner were laughing at you.. There are alot of great workout clothes that are far less expensive and aren't cotton based. Oh, and cotton is great on a causal ride around town.
2. Shorts on a cool day extract a stiff penalty from older riders. That constant wind chill on those legs is going to cause you some trouble that evening and the next few days. A nylon shell, warm-ups over those shorts is a very good idea. Bare legs in warm summer, otherwise...beware.
3. Riding with cars can eliminate all the fun of gettting out. Even if you have to trek your bike on your car rack for 15-30 minutes, regularly treat yourself to rides on long, dedicated trails. Very relaxing and uninterrupted.
4. Hi-tech pedals my be efficient, but platform pedals with toe clips, or mini clips, means you can wear tennis shoes or appropriate sport shoes you might wear around town. If you are biking in neighborhoods and want to stop and shop, dine, whatever, it's a good deal more fun to be wearing shoes you like.
5. Riding to destinations is fun, whether it be a gym, bookstore, whatever. A 30 mile ride really doesn't seem like much of anything if there is something to want to do at the mid-point.
6. Ipod type players are truly great on some days. Just be sure you have the type of headphones/buds that allow outside noises in. You will find you cadance pickup dramactically and you'll run on automatic, assuming you pick you music suitably. "Hey, were did those miles go?"
7. Us old guys probably have a bunch of tools and have spent too many hours working on our cars and houses. Yes, all of that transfers to your bike(s); dive into intimating over-haul and tinkering projects - what's the worst that can happen? (See below)
8. Hi tech and expensive carbon wonders have their place, but there are real joys to customizing, saving or building up old bikes. And they are dirt cheap. Parts on eBay and elsewhere. Ruin one of these sub-$500 bikes? Big deal. Hey, if you have over-priced over-engineered cars do you really want to repeat that experience with a bike that's going to demand to be babied, shop adjusted and worried about? Don't let the bike shop salesman talk you into a trophy bike.
9. Think comfort, regardless if mitigates the cool factor. With gel pads, an infinite number of seat choices, tire construction that runs from wires to floatation tubes, etc., 18+ gear choices, chamois liners, you can remedy pretty any discomfort you have returnung to biking. Be focused on what will make you comfortable to ride for hours adn hours.
10. It's just for fun, no one really cares about your equipment, distance and pace...unless you do. Enjoy.