Freeview boxes with slots for viewing cards virtually disappeared from the shops when TopUp TV stopped accepting customers for its 'old' service, which used those slots. (Their 'new' service requires customers to buy a special box, directly from TopUp TV).
However, now that Setanta has brought its prices 'into the real world' (they used to charge �8 per match, just to watch SPL games), there's been a resurgence of interest in using subscription services activated by viewing cards. So most electrical retailers now include a few 'card enabled' boxes in their range. For example, Argos sell this Sagem model at �39.99:
http://www.argos.co.uk/webapp/wcs/stores/servl et/Search?storeId=10001&catalogId=10651&langId =-1&searchTerms=5320345&go.x=0&go.y=0
If you've been perfectly happy with your old Nokia box, the Sagem would probably be a perfectly acceptable replacement. However, if you want an 'electronic programme guide' which covers a longer period, or you require two Scart sockets (which can make recording easier), you might want to consider this Philips model at �59.99:
http://www.argos.co.uk/webapp/wcs/stores/servl et/Search?storeId=10001&catalogId=10651&langId =-1&searchTerms=5320747&go.x=0&go.y=0
Chris