iMac and Apple TV and Netflix

Got it all!  Now I need your suggestions.

Using an iMac is so different from the iPad.  I'm sure I will adjust.  It's pretty awesome so far.

Apple TV.  We only have basic cable to I thought I would upgrade a bit and bought the AppleTV adapter for movies.

I signed up for Netflix.  Any opinions out there?  Netflix, Hulu, HBO?  What do I really want.  Netflix seems to have older movies.  What about watching TV shows?  Can I get HGTV, CNN, etc. somehow?

HELP?