I generally record at 24bit/44.1 since much of my material is destined to end up on a standard audio CD (however, I will be seriously trying 24bit/96 for future projects).
My use of plug-ins, soft synths and samplers actually varies wildy, depending upon the nature of each specific project. For example, I have recently being doing a lot of live recording into Cubase SX, where I am recording onto only one or two tracks (no plug-ins). This is achieved using a Mac Powerbook G4. This is in direct contrast to another recent project involving an orchestral arrangement where I have 30 or so MIDI tracks triggering 2 instances of Kontakt 2. This takes place on my music PC (Pentium 2.8GHz, 1GB RAM) in Cubase SX and also includes 7 or 8 EQ plug-ins and the onboard convolution reverb of Kontakt 2. This takes my CPU load to around 50 or 60%.
I think it is fair to say, therefore, that the same user could have radically different plug-in/soft synth counts for each project, and may not stick to the same formula for all their work.
Regardless of the project, I always feel safer having plenty of headroom both for my CPU load and storage performance, so I would tend to push up the power of my computer resources much higher than my real needs.