Thanks -- I'm well aware of the viewfinders on the non-pro EOS bodies; I had the 5 (A2E), which had a pentaprism viewfinder, but nowhere near as good as either the AE1 or OM2. Even my 40D is much better, although the crop factor helps in terms of magnification if not coverage.
My photography is an on-and-off hobby (family events aside), mostly walking around Washington DC and shooting whatever catches my eye. I enjoy the process as much or more than the product, so film works well for me when I don't need to deliver the Christmas pictures for Facebook ASAP :) I've been developing at home and scanning, but I'm going back to a wet darkroom refresher class next month and brushing up my technique in advance.
As I see it:
AE1 - I learned on it, so it's the most familiar and 'gets out of my way'. Prone to problems long term from the shutter and electronics, although the battery is common. Lens availability seems limited/expensive. Viewfinder is nice, and has a split-prism.
Nikkormat FTN - it's probably indestructible, and is compatible with a wide range of lenses I don't actually own, but could. The build quality of the 50/1.4 I do have is exceptional. Viewfinder is noticeably worse (dimmer/less coverage) than the OM2 or AE1, but nicer than the EOS5 I owned years ago. Wants a mercury cell for the meter, but zinc/air cells are available and an adaptor for silver oxide cells is $40, so not a real obstacle.
OM2 - nicest viewfinder of all, and I already have a 200/4 to go with the 50/1.4 Needs a new prism, but those are easily salvaged from Ebay junk, and I can do the work, so no big deal.
EOS - I have 20/2.8, 50/1.4, and 100/2 primes as well as 24-85/3.5-4.5, 28-135/3.5-5.6 IS, and 70-300/4.5-5.6 IS zooms, so I'm pretty well covered for glass. Too bad that between the lens design and viewfinders, it hasn't been fun to use in a MF/film mode. The 24-85 is my basic walking-around lens. If I go this route, it looks like an older 630 is a decent bet, or a newer 1n or 3, but not much else in between.
Going back to the darkroom probably just has me overthinking this. I have everything I need, and more, but it's hard for me to not want to rationalize this down to either 1 film and 1 digital or even just one system altogether. What do other who shoot both film & digital do?