I personally hate grinding levels through questing. But only in some quest areas. Some are great, and have good story lines, whereas some are horrible and I can't stand to quest there at all.
true.. I think of it as leveling as mandatory and doing so makes gold (usually) and rep farming is optional.. Ive grown to hate the leveling (im only 52 lol).
I think the worst grinding is leveling. Grinding reputation is pretty easy and sometimes fun (usually rewarding as well.) Grinding money is easy and enjoyable, I'd rather grind money than either rep or levels.
I've voted for reputation, as both money/levels are easy to gain, but there are far to many 'standings' to gain reputation for. As a result, it would take a very long time to get all of them to 'exalted'.
I hate rep to start with, wow it just feels so pointless, then there's leveling, you just wanna find the fastest way possible tog et to 80, atleast with gold you get that good feeling hwne you succeed