DaveMage said:
I wonder, though, how much seeing all of the d20 products out there affects those that may be just entering the hobby (as a DM).
I noticed that you overlooked another big monster of a setting, Forgotten Realms. And remember that every generic 3E book relates to the default setting, Greyhawk. I'd say that WotC's own settings stack up there as well, setting a rather high bar for other companies to guage themselves by.
Keep in mind, however, that this saturation is, indeed, what WotC wanted (although the economy was still in an upswing when the whole OGL thing started). The entire idea is that WotC can select items from these releases to be included in the main body of the SRD (infact, the upcoming Unearthed Arcana is the fulfillment of this ideal as it includes such items for just that purpose). Yeah, some of the stuff's crap. Some of it's also better than the Core product line. A lot. No, let me reiterate: A LOT.
But also bare in mind that, with the economy on the downward slide and such a wide variety of choices available, it really is a buyer's market. Don't just walk into a store with $50; Read the reviews and choose your purchases wisely. Get to know the companies; you'll find that each tends to have their own leanings regarding style and flavor, with their products often "feeling" related with some consistancy even if not mechanically intertwined.
Try to stear clear of settings unless the product is definately something you want. There are plenty of non-setting books available that easily conform to most typical settings with ease. There are also (as Buttercup pointed out) plenty of one-book settings that are ripe for the GM to develop to his own accord (in theory, every setting is a one-book setting, with the rest being gravy). Also look for stand-alones that are intergrated regardless. For instance, Bastion's
Alchemy & Herbalists and
Arms & Armor are stand-alone, but the entirety of these books is considered "default" in Oathbound (this, I believe, is true of nearly every Bastion release, with perhaps their work on mythological deities being the only clear exceptions).