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
My front speakers are Monitor Audio PL500's, center Monitor Audio gold 350, rear are Monitor Audio Bronze 6. I'm thinking SVS PB 2000 as a relatively inexpensive sub.
Yes, the sub setting is set to no sub.
I called Monitor Audio and they recommended the Gold 350 or Platinum 350 center channel to match the Pl500's. It's my understanding that the rears aren't as critical.
I really have great experience with Hsu, similar pricing to SVS, but better looking cabinets I think.

Best,

Erik
Although its been a couple of years ago, I had an HSU sub and don't care for them. If it was for music it would be JL Audio, but for HT I submit SVS is a safe bet, offering good value. 
My recommendation would be for a pair of smaller (10-12 inch) subs rather than a single large sub.  And use LF acoustic room correction if possible.  You can often find a used Velodyne SMS-1 listed online, if your AVR or processor doesn't provide it.

db