After years of being against True Blood, a friend of mine convinced me to watch it and lent me the first 3 seasons. It took me a week to watch the first three episodes because I found them painfully boring and the show quite bizarre. But then, arriving at episode 4, I have been hooked ever since. I went out and bought the 4th season and am half way through season 5 currently. Love the show so much. Can't get enough of Eric haha. 5 seasons in 3.5 weeks - safe to say I'm addicted.
As for TVD, I've only just started watching it. I bought the first season without knowing anything about the show. I will admit that it's very different from BtVs, AtV and TB and I find it pretty pathetic sometimes. But I will continue to watch it. Up to episode 11 of season one. I was keen on Stefan to begin with but now I'm shifting towards Damon. Always a sucker for the 'bad boy'.
I thought I was against other vampire shows because of their difference in mythology, but it wasn't as hard/bad as I thought it would be.
And yes, also a huge Supernatural fan. Bought all 7 seasons and couldn't watch them fast enough. Winchester's FTW!