A good scuba diver, however, has quality gear, and dives monthly.
Not just once or twice a year.
Therefore I maintain that while in grad school or med school, this is not the time to begin a scuba diving sport. Wait at least until you graduate.
Oh come on, give her a break...
Don't listen to this nonsense, start diving when you want to and don't worry about whether or not you confirm so someone's arbitrary view about what makes a "good" diver. Besides, you'll probably be working yourself pretty hard at school, you'll need some nice breaks.
As far as money goes, just waltz into any dive shop and tell them "I'm going to be a doctor, and I want to start diving. I'll need a full set of gear..." and watch as they start doing handsprings across the floor while offering you unlimited credit.
As far as a serious recommendation goes, first buy a wetsuit that fits you perfectly, and follow TS&M's advice about the BP/W set up for tropical diving. The fewer straps and less padding, the better. You need to understand that the way a BC fits/feels underwater is nothing like the way it seems on land, particularly in a dive shop.
The reg could be lots of things, zeagle envoy, aqualung titan, SP MK2/R190, among many others. They all work fine. It's best if you can get it serviced where you are diving in case something comes up on a trip. For the caribbean, this favors mares, oddly enough. But aqualung and SP have shops and parts available almost anywhere as well.