I would like to recommend the Artificer's Handbook. Ypu, I am biased but there are great reviews here and a few threads here and at Mortality.net that should convince ya.
With a similar self-implaced budget I've placed an order for the entry pack of the D&D minatures. My FLGS didn't order them (having been burned by Chainmail), so I didn't get the impulse buy satisfaction. [sigh]
Rationale: I run my own campaign world and don't see an immediate need for more sourcebooks, and don't need pre-made adventures. I am tempted to get Midnight eventually, but not yet.
Any PDF by Malhavoc that I don't already have is a likely temptation as well...