So I'll start. Me personally I love watching GP2. But in GP2, interestingly, I prefer to watch the races, while in F1, my focus lies more on the championship tables. A close championship fight seems more enjoyable to me than a close fight on track, whereas it's the opposite for GP2 for me. I also love watching the DTM, as I do love watching people race sportcars (albeit a bit more purpose-built for racing) and I do love the great close racing
A friend of mine recommended watching superleague, and Indy too.
Having said that, everything else seems to be slow when you've watched F1
But the racing is fantastic (like ALMS, but longer races).
