V8Supercars beats everything easily in entertainment other touring car series are:
too uneven (one driver that can drive in fast car and alot lof losers) or have too many wreckers (btcc, dtm, wtcc), or
have too many random in series homoglation tweaks to keep it interesting, sometimes
the tv production plainly sucks (all GT racing I've ever seen, it's not my job to keep track of all team strategies to keep track of who is winning), some
drive on too boring tracks (like only turning left or not turning at all)
Memorable mention:
Rallycross (espesially when they have the alternative turn you have to take once) (I dont think alla series'se got that)
SCCA Runoffs (all cool US amateur series final, formula vee, protorypes classed by displacement to weight ratio etc.)
Truck trial, Icelandic formula offroad, hillclimbs etc. Fantastic to watch once in a while, but I surely cant geep glued to the screen for 1000km's worth of racing as I can with Bathurst.