Any great ones asides from the stock Cakewalk one?

Not sure what you expect from a bitcrusher. PSP Nitro, Izotope Trash, Fabfilter Saturn do bitcrushing and have demos

Bit Crushers are not reall my thing, but you could do a lot worse than D16's Decimort

I'm looking for another flavour.  Thx for the suggestions!

my favorite (old, but still relevant) is the 3lit3 r3duc3r (or elite reducer). it just sounds the best to me and has lots of simple automatable parameters.
drums sound delicious through it.
http://www.virtualcreations.de/download/elitereducer126.zip
http://www.virtualcreatio...load/elitereducer2.zip

download links aren't working right now for some reason?

BitSpeek from soniccharge is nice :)

http://soniccharge.com/bitspeek

This one also works as a little monophonic vocoder, since you can (if you want to) control the pitch with MIDI-notes

$29 is a really good price too :)

You must not link directly to the binary on virtualcreations audioplugins webpage. Better is www.virtualcreations.de
 
There is also a new version of Elite Reducer 2 (version 2.1) for Mac OSX and Windows available now.

"Great bitcrusher" is an oxymoron in my world 
 
A bitcrusher works by truncating data to some user-specified word length. That's it. There aren't a lot of possibilities for adding flavor and features to such a simple process beyond letting you specify the word length and applying before/and-or/after filters.
 
As mentioned above, D16's Decimort has about every knob and button you can imagine tacking on to a bitcrusher.

I caught bitflipper in flagrante delicto:
bitflipper is a bitcrasher!

Flippin' bits is OK. Crushing them is an abomination. There are starving engineers in the third world who are desperate for some bits, and here we are just throwing them away.