xOBDIVER2009
what i might say here could be ofensive to some of the people here, so i will appoligize in advance
as you are new to diving, i agree with the rental of equipment first. this does give you a chance to use some diferent type of gear and learn how the feel in the water. some regs are eaiser to breath than other, you will get the feel for weight intergratred bc over a weight belt, try a back inflation over a jacket style or hybrid type bc ect...
as for the ocean compatiable reg, they will all work fine. the things you would be looking for is if you will dive in cold water or not. if you do, you would be looking for a reg with an enviromental seal or other designed specificly designed for cold water use. another thing you will need to think about is if you will buy a piston or a diaphram reg. diaphram regs are extremely easy to take care of. get out of the water and leave your reg attached to a tank, and rinse the body and attachments off and your done. if you get a piston reg you will have to spend a little more time making sure you rinse out the holes that allow the water into the reg to adjust the pressure. if you dont do this, you will have salt and sand get traped in the holes or on the o-rings and the reg will not perform as good as it should.
now for the long heated debate of buying online vs. the local dive shop (lds) i would say the lds. i do work for a shop that my parents own, so my oppinion my be a little bias, but you will understand where i come from.
you can go buy your gear online, and may get a lot of help while on the phone talking to the sales person, but this is not allways the best. nothing beats getting to hold the gear in your hand and play with it. next, how will you know if it will fit you properly with out getting to try it out first. if you do buy your gear online, they might not sign you owners book, or show you how to register your equipment, and than you will have a hard time getting your gear serviced at a lds, and will be stuck shipping it back to the place you bought it and paying the shipping fees.
if you buy from a lds, you will have a chance to go try the gear out in the pool before you purchase, along with the benefit of the personal service you will recive while looking and getting fitted for gear. also if you tell them what type of diving you will be doing, hopefully they will not try to sell you the mose expensive gear in the shop, but assit you with question and show you the most approperiate gear for your needs. next they will help you fill out your warenty registration so you can have your gear serviced at any authorized dealer of that type of gear. finally if you continue to go to one or two dive shops continually, you will make a good customer relationship with them, and if you have a problem with your gear they might look at it and fix it for you free of charge, and you would have your gear back the same day
i hope some of this info if helpful to you and you have a good experiance when you do get your gear.
the last bit of advise i can give to you is to read the back cover of a Dive Training magizine and read the back cover about buying gear. this is a good insight into the reasons behind all of this
i dont know where you are at in virginia, but if you are not to far from Hagerstown Maryland, stop by the shop and we would be glad to help you out with any questions you might have