I recently returned to diving after many years away and have bought a lot of new gear. Before doing so, I spent hours reading posts on this and other boards for info and learned a TON. You will get a billion brand opinions, but here are a few general absolutes (oxymoron) on buying equiptment IMHO.
If you buy online you will save LOTS of money. However, you will not have any decent service, which includes advice, help, adjustments, opinions, maintenance, and good will. I bought some stuff online and had little or no help (except from this board). But after 2 leaky masks I went to my LDS and tonight the DM is bringing me several to test on the dive at no charge. Gee, what cost me more? Three masks or one? However I DID save 300.00 on my new BC. I am buying a 7mm wet suit from my LDS for 80.00 more than online because their service is so great and it is the same wet suit as the one I've been renting from them- and I know it works great! In fact, I highly suggest you rent your gear for a while so you can get to know what works best for you before you buy (another reason to use your LDS).
Which LDS to use? Where did you get your C card? Are you happy with them? They have invested in you during the class. If you are happy with their service, I would use them and enjoy the benifites of becomeing a long-time loyal customer. With that said, unless you have money to burn, sometimes it would be crazy not to buy online. For interesting opinions on buying from your LDS or not, do a search for posts on this issue and read the opinions of GENESIS and MikeFerrara. Divers Union VRS. Dive Shop Owner. Very enlightening.
I love buying new gear and fine tuning it to make it become a part of me! So enjoy!!