Hi Ric,
This is an easy one. Continue to build up your combo 2-channel/HT system. Get the rear speakers installed, go through the setup routine in your receiver and try it out with some of the types of movies you enjoy. If you find that you would like LFE (Low Frequency Effects), or you need some additional bass in your HT system, add the sub and re-do the setup routine.
For me, if I was going to go through the trouble and expense of adding HT to my 2-channel listening room, I would definitely want a sub to add the final dimension of sound to the HT experience.
As you know, the sub will have no effect on your combo system when listening to 2-channel music, so it's simply a matter of "do you want/need LFE or additional bass when listening to HT sources?". Your choice.
This is an easy one. Continue to build up your combo 2-channel/HT system. Get the rear speakers installed, go through the setup routine in your receiver and try it out with some of the types of movies you enjoy. If you find that you would like LFE (Low Frequency Effects), or you need some additional bass in your HT system, add the sub and re-do the setup routine.
For me, if I was going to go through the trouble and expense of adding HT to my 2-channel listening room, I would definitely want a sub to add the final dimension of sound to the HT experience.
As you know, the sub will have no effect on your combo system when listening to 2-channel music, so it's simply a matter of "do you want/need LFE or additional bass when listening to HT sources?". Your choice.