Thanks Jon (and dk and Joe), re-calibrating the monitor has improved things immensely, but I will, as usual, make a note (not mental, as that would probably be pointless grin) of all the suggestions.
One thing I hadn't done yesterday was to connect the Canon Pixma MP630 printer/scanner/etc to the Macmini, but after I did it today, it was not detected. The printer driver was not listed - in fact little or nothing Canon was/is listed - which seems most peculiar as I checked out the Leopard compatibilty even before I purchased the printer/etc and had read an Apple document listing the MP630 in it's "compatibilityness". Anyway, I installed the driver from from the Canon disk and it now works, albeit a slightly different layout. This also leads me to another query, whereby I could not find the printer utility (what's it called Jon?) which I know existed on Tiger. Any suggestions?
Finally - I will post any other problems/experiences I have with Leopard in the more appropriate place - reverting back to my "harping on" about Spotlight, Jon, I seem to recall that you have, in the past, "championed" alternatives. I have "VersionTracked" a couple - EasyFind and Find Any File - and was wondering what your experience has been (with the alternatives I mean shocked blush).
Sorry for "going on" and thanks again all. Regards. Mike