Are the more expensive ones easier to play?

Generally, yes. If you want a decent kit that will require a lot of soldering, the Paia Theremax is the way to go. It's very reasonably priced, especially if you supply your own cabinet: [link]

Playability is OK. The biggest complaint I've heard about it is that the volume control is close to binary -- It's difficult to be very expressive with it. However, there are people who've improved it and there are supposedly mods out there if you look around.

If you really want to learn to play, the Moog Etherwave is the best bargain out there: [link] (5% off with code AFF01) I've linked to the kit version (there's also a finished version) because it will save you some money, but if you're looking for a challenging project, this isn't it. It comes with a finished circuit board to which you'll only need to solder the knobs and antennae. The final product is an excellent instrument -- It's the one I used for many years.

If you go with the Etherwave, my link above is the cheapest I've seen it, plus it's my affiliate link, so please use it :)

If you really want to learn to play, the Moog Etherwave is the best bargain out there: [link] (5% off with code AFF01)

Ooh, that one looks nice. I think I'll just make sure I'm getting an X-mas bonus this year before I buy it.

Is there a term for musical instruments that can play any pitch and that force the musician to find the right notes by ear? Like, say, the trombone, violin (and other fretless instruments) and theremin? (But at least trombones and violins let you memorize positions to get the right pitch for notes.)

Is there a term for musical instruments that can play any pitch and that force the musician to find the right notes by ear?

There should be!

Hey, I just leaned of an even better deal with the link I gave you above. Instead of AFF01, use coupon code 15%COUPON at checkout for a 15% discount on your InstrumentPro order over $99!

a 15% discount on your InstrumentPro order over $99!

Yay!

Any idea how long that deal lasts?

ION, Jon, did you see I bought this? [link]

Sadly, my Arduino is too old, so I have to wait for the one I just ordered to show up before I can try it out.

The sound it produces is pretty basic/retro-synth, but it has source code I can play with... getting into the algorithms of a synth sounds like fun.

Is there a term for musical instruments that can play any pitch and that force the musician to find the right notes by ear?

Aren't they called variable pitch instruments? Musical saw, slide whistle, fretless bass, theremin....

I think I need to spend a weekend afternoon just fixing my iTunes data.

Dude, I'd need way more than an afternoon.

We say fretless to mean even things like trombone. But that's just shorthand, not anything proper.

ION, Jon, did you see I bought this? [link]

Neat!

No idea how long the 15% off coupon lasts. Don't Delay! Buy it today!!!

Pylon Interview and download over at the Village Voice.

These would be my Tom Waits essentials:

Small Change
Closing Time
Swordfishtrombones
Franks Wild Years

I am going to have to get Bone Machine, aren't I?

My long lost HS friend was telling me that she had tickets to see Tom Waits in 1999. She was pregnant at the time, and her son came early, two days before the concert, so she had to give her tickets up.