I'm so glad I went Pentax all those years ago. Between us, my partner I have a collection of manual focus Pentax K-mount prime lenses that are still worth over £1500. Luckily Pentax digicams accept their old K-mount lenses.
The smaller frame size of the digicam is a nuisance (especially as I lose the extreme wide angle my 20mm F4 used to give on 35mm) and the lenses work in manual focus mode only. However, in practice none of this has been a problem.
I bought a refurbished 1stDx digital SLR body from Pentax a couple of years ago for £250 and I'm really pleased with the system. I mostly use the camera in complete manual mode (just like my old SLR) with TTL metering and take all mu photos as RAW images (not JPEG). I'm short sighted and wear glasses, but I don't find manually focusing the digital camera any more difficult than it was with the old film SLR and the benefit of not using film and having an instant view of the photo taken is just marvellous. In terms of picture quality, the digicam pictures are as good as those I took on Ektachrome 200 ASA slide film and and scanned using a high-end slide scanner in the 1990s, and a little better than any I scanned from print film negatives.
One thing that is *really* noticable, though - the difference in quality between my old Pentax prime lenses (non zoom) and the those taken using the Pentax "digital" AF short zoom lens that came with the camera. The old lenses are far, far better. The modern zoom is no better in terms of lens abberations (both chromatic distoration and barrel distortion) than my old Tamron manual zoom from the early 80s. Disappointing - I would have thought zoom lens technology would have moved on some since the early 1980s. The practical upshoot of this is that I very rarely use the zoom at all and usually have to take a bag of lenses with me when I go out to take pictures - just like I always had to with a film SLR.
In terms of your olympus lens problem, I'd certainly look into finding a digital body that could take your old lenses by means of an adapter of some kind, unless your main reason for going digital is to use the other features that digital cameras offer (like anti-shake & auto-everything). Olympus lenses had a very good reputation and may well be optically better than some of the modern offerings.
tekno.mage