Is a Sub required for HT


I'm a 2-channel guy that decided to add a separate HT system. I currently have a center channel speaker and AV receiver running through my 2-channel preamp's HT bypass. I just purchased rear channel speakers. I hate subs for 2-channel, but are they required for HT?  
ricred1
I have a SVS Sound Cylinder in my HT setup. I like it in that system for music and music channels. There are a lot of good options out there.

Regards

I watched the Jungle Book last night and the SVS  PB- 2000 did exactly what I wanted. In a HT context it offers very, very good value.
I like a sub in my HT system for movie effects but I don't like a sub in my 2 channels system with full range speakers.