Sine wave generation is a perennial problem.

Solid tantalum capacitors have a lot of advantages: very low inductance in surface mount packages, ESR low but not so low that your LDO regulators start oscillating; and good capacitance per unit volume.  Unfortunately they're also prone to burn up when mistreated, which makes many engineers wary of them.  This war story, entitled What a Cap-astrophe! talks about how to treat them properly, and how a bit of TLC after soldering can restore their full performance.

For RF folks, one of the perennial quests is for better frequency mixers: lower distortion,
lower power, better spurious performance.  FETs can help.  Nowadays CMOS muxes are the devices of choice for HF mixers, but to get the best performance, you still have to know how they work.  Ed Oxner was a long-time Siliconix apps guy, and his paper on High dynamic range FET RF mixers is still right up there with the best. 
(From a Siliconix databook, 1985.)  The FET mux approach is often credited to Dan Tayloe, but since they work just the same, the "Tayloe mixer" should really be called the "Oxner mixer".

Erroll Dietz is a remarkable fellow.  He started out at National Semiconductor as Bob Pease's
technician, and rose to become Chief Technology Officer.

Sometimes it's useful to add supporting documents, schematics, scope photos, simulations or other things to Usenet posts.  By popular request I've added links to some of these, in no particular order.