I do 99% of my work with a 20D, but sometimes I'll buy Leicas (M3 usually) on ebay, use for a while, then sell them.  It ties up bucks, but it's worth it.  If that's too rich for your blood, you can get a REALLY old Leica screwmount for a couple of hundred bucks, and shoot great stuff if you've got a light meter, or try the old Canon rangefinders.  You can get them for a song, and they're great.  Also, some of the old (50s vintage) Canon lenses are right up there with the Leicas (and even better coatings on some).

I don't.

I shoot with a sony f717 and love it. it can be light and minimal, or I can hook up studio lights to it.

When I am not using my Mamiya RB Pro SD or my Nikon FM-2 and F-3 I like to put b+w infrared film in both my swivel lens panoramic cameras. One is a Widelux (from Japan) and the other a Horizont (from the former USSR) Both are dogs and unpredictable but sometimes the results are exciting.

TLR's rock, I can only afford the Mamiya C330s, but its 80mm and 135mm primes are razor sharp.

Rollieflex/cord is next on the list, when I find a good cehap one.

Also a lot of can be had a Zeiss folder, no lcd review though!