As was mentioned earlier, try before you buy. You could do some research on the web and in dive magazines (LDS probably has some back issues) such as Rodale's where they do some testing and rating of equipment. However, keep in mind, Rodale's does NOT test ALL scuba gear so if you see something you like but it wasn't reviewed in Rodale's, don't discount it as not being good.
You might be able to get a better price from an LDS if you buy several pieces of equipment at once which doesn't mean it all has to be the same make. If that's not possible, then think about which pieces you want first. If you do a search here, you'll see that people have different opinions on what order to buy equipment in. Personally, I would recommend the regs and BC first since they are life-supporting gear. Rental equipment is not usually top of the line stuff and can get abused by renters. I'd rather wear an abused wetsuit than use an abused set of regs!! I've had rental regs crap out on me at 80ft (twice!) which spurred me to buy my own. What's best for you might be to buy another piece first.
Decide what type of gear you'll need. Cold water? Warm water? Both? If both, you'll want regs that can withstand chilly temps which will probably have you looking at an environmental first stage. Also a thick wetsuit or possibly a drysuit. Your BC will have to have enough adjustability to work for both a wetsuit and a drysuit (be sure straps don't interfere with the drysuit air valve).
BCs come in different styles. You probably used a jacket-style in your BOW and they are just fine for many people. I have a back inflate which I love. I can't envision ever going back to a jacket style. Perhaps a backplate and wings would be your preference. Think about if you will be travelling. How compact will it get for packing in a suitcase? For the record I have a Zeagle which is very adjustable and not too bad to pack.
Take a look at what other divers are using. Ask them what the like and dislike about their gear. Keep in mind that what works for another diver, is not necessarily right for you. Fit is everything!
So, try, try, try.
Here's what I have:
regs - Oceanic Delta 3 (2nd), Delta 7(octo) w/ environmental 1st
bc - zeagle Concept II (sport - not made anymore), weight integrated - but I still use a belt
wetsuit - BARE 5/4, Atlan 6.5 (custom)
drysuit - Abyss 4mil compressed neoprene (custom)
Diverlady