I think Roswell would be perfect for you, it's older, but I love the show. Only 3 seasons though. I got really attached to the characters haha.
Buffy the Vampire Slayer is my all time favorite show, 7 seasons of it. Similiar to Supernatural, only better in my opinion. The spinoff Angel isn't as good, the last season kinda sucks, but it's still a must see. I think Angel had 5 seasons if I remember right, so that's around 12 seasons to catch up on.
Doctor Who!! Please check this one out!! I think you'll love it. It's a british tv show. It's AWESOME. You don't want to get into it's spinoff show Torchwood though, it's mildly different from the Doctor and has more inappropriate stuff. Start with the new Doctor, but there is also Classic Doctor Who.
Once upon a Time, made from the creators of Lost. It's a fairy tale type show, also pretty awesome.
Malcom in the Middle is also a great tv show, I'm 25 and I grew up with this show. Still enjoy watching it.
Glee is pretty good, too! I didn't think I'd care for the musical singing teenager type show, it sounds kinda lame, but it's very very entertaining.