Pentax K1000, It's a Spotmatic with a K-mount, But I usually have a Canon EOS body along with my "modern" kit.

I have two M42 Argus/Cosina STL's in one kit, decent little cameras, especially when you can get them for $5-$10.

I still want a black Nikon FM or FM2, even though I have no Nikon gear or glass. Just a beater FM and a 50mm.