Sometimes (not often) a person will ask me about what they can do to get into bicycling, or they'll put out a few feelers about getting started bicycle commuting and do I have any advice? I start out with "what kind of bicycle do you have" and inevitably it's old and heavy and does not fit. Then I hand over my very technical and specific advice: "Get a nice bicycle." I smile hopefully. The person shuffles their feet.
They tell me that before they spend any money they want to first see if they'll do any bicycling and this is when my heart breaks a little. Bicycling is not a lot of fun on an old poorly tuned vehicle that does not fit. The gears don't work. It's heavy. It's slow. I appreciate the sense of not spending money on something you will not use but you have to appreciate that if you had to push your car to work each day you might not want to drive anywhere either.
So then they ask me what kind of bicycle to get as if I knew shit from shinola on the topic, which I do not. But I still have an answer and the name of that answer is "get a bicycle that you like." The bicycle that you like is the one that you ride. And while we're on the topic, to any engineers out there still fighting the text editing wars? Vi or emacs? Same goes for you. The right tool for the job is the one that works for you.
How do you figure out which is a bicycle that you like? Go to a bicycle store. Figure out what size of bicycle is correct for you. Try a lot of different bicycles. You can take the bicycle outside after completing some paperwork showing you are not a car thief and then you can really ride. Definitely do not just sit on the bike in some department store. Come in your bike outfit and ride and keep riding until you meet the bicycle that feels great. The brakes will be in some place that makes sense for your hands. Your back won't hurt. The gears feel just right. Now go home. Come back a few days later and ride the bicycle you liked all over again. Do you still love it? Are you muttering endearments under your breath? That's the one. Buy it.
Also for the sake of your romantic life, spring for a decent bicycle seat.