I think different people use the IMC in different ways. I do a lot of en-rout IMC, but being single engine/ no de-ice limited I tend to avoid flying if the cloud is less then 1000 ft AGL.
I have never had to hold, and I would divert if things started to deteriorate. I stay current on approaches, but have only had to do two for real in 10 years, both VOR/DME, with no holds and two planed diversions available into airports with ILS if I needed them.
If I were based at a field which had an ADF element as a compulsory part of the published procedure I would make very sure my ADF was in good order, I would practice it regularly, and I would practice holds if local procedures meant I would need them. In my case non-of the above is true.
On the GPS question, I find it is very useful to be able to draw a picture in my mind of what is happening based on the traditional aids, and then cross check by glancing at the GPS. I find the discipline of doing things in this order to be hard to keep up as the GPS is much more accurate, but I always assume it is about to fail.
If the CAA approved GPS for primary navigation it would hugely reduce workload in the cockpit, but they would also have to insist on proper training to understand the limits and pitfalls of the technology. A badly set up GPS being obeyed regardless is a huge safety hazard. I work in the computer industry, and garbage in garbage out is very relevant to GPS systems.
Rod