I am about 95% digital now. I still have a 4x5 system though I rarely use it these days (last year I exposed all of 10 sheets of film). My online portfolio is a mix of a variety of formats, from Medium Formats
(645 and 6x7) to Large Format (4x5), and the more recent work is practically all digital.
I currently use a Canon 5D (previously a 1Ds) with a selection of Canon "L" zooms, which I find very flexible and convenient for field work, and providing excellent image quality. My favorite lenses are the 70-200/4L and 17-40/4L. These are usually the 2 I carry with me on hiking and backpacking trips. I prefer to work in fairly remote places, away from the crowds and the well-known icons.
In a way I never really changed my working habits from the Large Format days. The large camera and manual process trained me to take my time, to concentrate on visualization and careful composition, and not rush into making images. The digital advantage comes into play in the field when metering, and in allowing me to experiment with multiple compositions, and of course working with raw captures gives me
unprecedented control over the "developing" and processing my images. Recently I started doing more and more multi-exposure stitched mosaics that I find as good or better than my 4x5 scans.
I work in Photoshop (recently upgraded to CS3), convert my files in ACR, and use a Mac Pro for my imaging workstation. I'm a big fan of the distinctive look of pigment inkjet prints (mostly Epson) on cotton
rag papers (Hahnemuhle Photo Rag and Moab Entrada are personal favorites).
It's a great time to be a photographer. There's so many powerful tools and options out there!