Whizbang Dustyboots
Gnometown Hero
Because D&D is the easiest to find players for and is the ideal gateway drug for other roleplaying and because, since they're not trying to sell to the same huge audience, third party D&D books tend to be a lot quirkier and more flavorful.i hear/read this all the time and can't imagine why you would want to BOTH stay with D&D AND buy other company stuff...
I've got books with procedurally generated demiplanes and urban campaign books large enough to kill a housepet if they fell on them, neither of which WotC is likely to make anything like any time soon.