Where do I start with a home theater system?

Yes, stereo sound with good external speakers is better than tv speakers. But what you get is stereo sound.Just running two speakers in the front will NOT give you a "theater" performance. There is information going to at least 5 speakers plus a subwoofer. If you do not have these speakers you do NOT get the sound of the movie.

Your question is about home theater.

What you need....

Two front speakers, These are your large speakers,

a center channel, # this is one of, if not the most important speaker# either get a third speaker of what you have or get a center channel from the same series and manufacturer, as your front two. So try to get the best one you can That matches the fronts.

two rear speakers, they can be smaller than the fronts.they do not HAVE to be from the same manufacturer but it is a good idea to stay with the same manufacturer and series of the others.

There is nothing wrong with using older speakers for surround sound. Or for that matter two channel, if you like the sound then keep them and same the money.

Subwoofer, Probably you second most important speaker after the center channel. This can be any manufacturer, There is a great deal of opions and information on choosing this speaker. Depending on your room and what you are looking to to get out of it.

Processor....
I do not know what your current equipment has as far as connections.

There are TWO ways of going about the processing of the movie soundtrack and for that matter music concert soundtracks. #This is where NEWER equipment is needed#

You can,
1# get a AV receiver #has amps in it# or a processor # no internal amps# to decode the particular disc you are using.

This is a good idea because you probably want "room correction" to get all of these speakers working well with one another.

In this case you plug in your Blu ray to this and IT decodes the material, you intern plug your tv into the processor or receiver.
you use the "preouts" to your amps, if this is avaible #on a receiver# or use the outs on the processor to your amps. There is more to this, but I just want to give you the basics.... You will still need a Blu ray player.

2) get a good blu ray player that has multipal outs. I would imagine you would use HDMI for your tv, so it need one of those. and outs to connect to your stereo pre amp.
These do not have "room correction" so you might be in for a long haul setting up all of your speakers...

I would recomend room correction. so get the newer processor or receiver.

Check out THX website for speaker and seating placement. Controling the light in the room will help a great deal even with a plasma.

If you would like to speak to me email me @ billbaranowski@yahoo.com

If you can keep the HT separate from the two channel system all the better for your two channel. Then start from the beginning and go cheap. You don't need to spend a lot of money to enjoy home theater.

I suggest a new receiver with the most up to date codecs and room correction. 7.1 is better. You rarely, if at all, hear of anybody going back to 5.1. The receiver doesn't have to be top of the line. The 7.1 matrixing of 5.1 media works very well and creates a much bigger surround field even in a small room.

Its best to use seven matched speakers but using the matched center is fine. Stay small and thrifty with the speakers and hopefully used.

A good sub is what makes HT fun so budget more here. Again used, you'll have room correction in your receiver so you don't need a sub with correction software.

Unless your already a big movie renter I'd forgo the disc player until later.

Just my opinion, this is from previous experience.

Stick with Two channel!

You can try out home theater if you would like, everybody has their preference.

I went from Two Channel to home theater back in the 90s and promptly returned to the better sounding 2 channel and of course the constant upgrades to the latest processor.

But for some reason I thought that with th advent of HD, Blu-ray players and HD sound along with the fact that a lot of hi-end company's were producing surround sound processors, I would jump into the band wagon again. I went with a 7.1 system, after spend countless dollars buying large, full Range Speakers for all channels including a pair of floorstanding full range speakers for the center channel. Purchasing big Tube amps for All channels, including bi-amping the main speakers. Top of the line Blu-ray player and hi-end Processor and yadda yadda yadda.
Brands varied as I tried to tweak in the system ranged from, Von Schwiekert, Vandersteen, Acoustic Zen, Cary, McIntosh, Denon, Jolida, etc.

Yes, the system did play movies and to the laymen it was most likely awesome. But for me the surround processing varied so much film from film it made it hard to get things right with out constant adjusting of the settings. The processing also robbed the full range speakers from doing their job and would take information away from them, what I mean by this is if your listen to the movie in surround and then switched to stereo the sound would change. No matter what I tried I could never get things just right. So I went back to 2 channel and haven't regreded since.

So besides the cost factor of going multi channel, I don't think you really gain anything over a quality 2 channel set-up.

But if you want to go the home theater route, all I can suggest is that you buy a McIntosh Processor. I have not tried them all but I have tried out various budget models (Outlaw, Marantz, Rotel) and I have tried out some hi-end models (McIntosh, Cary, Theta). The Newer McIntosh Processors are quite expensive but as long as you can due with-out HDMI switching then I would recommend the MX-119. Wonderful sounding and probable the easiest to adjust. If the McIntosh is too much and you want to go budget, i liked the Outlaw Processors (no HDMI switching). If you have a nicer Blu-Ray player with 7.1 analog out you can still benefit from the HD sound.

Of course if you want have a dedicated theater room designed and built, i am sure your results would be better than mine.

Regardless of what you do I hope you enjoy the music and or movies!

Based on your current system, IMHO, I would get a center channel compatible with your planars (maggie?); a 3 channel power amp with similar characteristics similar to the levinson (parasound, classe or Levinson if they make one) a cheap processer ( the Emotiva umc-1 is pretty good for $500 and you can "pass thru the signals from your 2 ch preamp thus keeping your 2 ch listening in tact. Then I would get the OPPO 95 or 105? for your surround sound player and use the analog ins to your processer (quality will be better than any costing $2-3K)
And of course , subwoofers. This would give you a great surround setup while still enjoying your 2 ch.

PS I have a surround sound using Apogee speakers with good electronics--stunning!

If you go 7.1 as Vicdamone advises, make sure your room can accommodate all the speakers, especially the back surrounds.