ok, well I'll give you an idea of my cards quality...
my wife was home late the other night from work so I recorded law and order for her...
the picture quality is fabulous, on my display while we sit on the bed or the couch, its almost the same output as digital television...
admittedly this was @ max quality setting (ati's dvd quality) and 2 hrs of record == 5 gigs (including high quality audio)
however going from my hauppage card to the ati tv tuner (the new x800 series and standalone hdtv tuners are supposedly better for regular tele, plus they are hdtv capable)
television reception is sharper than on regular tv's mainly coz of the smaller dot pitch but you have to sit @ a distance of around 6 feet or so otherwise it looks a little off... you can make out the lines a lot easier when you are closer and it makes it look worse...
wrt blockiness, I dunno if the built in hardware filter works for VHS conversion to DVD or whatever, but for movies and channels, there is an active de-blocking feature that works hand in hand with divx (for recording and viewing purposes) called fullstream and it actively works to make images clearer w/o the blockiness...
I had a low/mid end hauppage and i had an msi tv@anywhere master tv tuner... the ati tuner is the best I have had personally... mainly because of the feature set... and the remote control