Hi,
My first post. I'm an M42 camera user myself, the Pentax Takumar 28mm and 35mm would be the obvious suggestions as they are probably the best in the M42 mount. Also Vivitar made some very good wide angle lenses for the M42 mount and in my experience are very good and generally cheaper than the Takumars. I have a Vivitar 28mm and 35mm as well as various Takumars.
Prakticas were decent starter cameras in their day. I own an L and an MTL5, and while a little lacking in finesse, I think they are capable of producing excellent results, as your photostream shows. I find the shutter button to be in just the right place, like one of the first SLRs, the 1949 Contax S.
I particularly like your 'Nap Time' photos.
Here's a pic I took on my MTL5 and wet printed at home. The night shot is the Vivitar 35mm lens.