Mainly I start in LR. I use it as a catalogue for projects and will sort and do basic edits, crops etc in it. Sometimes that is all. However, in most cases I will either edit in one of the Nik filters from LR or, more commonly, use Edit in PS to move the image there (as a copy with LF edits), apply effects, layers, cloning. border and then save it back to LR. I will then apply any gradients I want to use and maybe tweak the curves before doing output sharpening in Nik Sharpener. If I want a JPEG for upload I will do it from LR but I always print from PS. I used to always start in Bridge but I find LR more convenient as you can quickly apply and synchonise adjustments there (I know this can be done in Camera Raw from Bridge but LR is a slicker front end).
When it comes to my main catalogue of images I don't use LR. It contains about 40,000 images and I use Media Pro from PhaseOne. When I shoot using one of the of the PhaseOne backs I use CaptureOne as the primary interface and then open the output from there in PS. Sometimes I will then import the final versions into LR but usually they are just indexed in Media Pro.
I miss layers in LR and decent borders and, although I can get close to what I'm after in LR, I find it quicker and more straight forward to follow the approach above. However, for work images where I may just want to make a minor adjustment to the white balance and exposure, remove a sensor spot and crop and sharpen, I would use LF only. For creative stuff I find I often want a tiny bit more control.