Is Marantz AV8805 good enough pre amp for McIntosh MC8207

I recently replaced my Marantz AV8801 (two generations removed from the AV8805) with a refurbished Marantz AV7704.  The price difference was over $3K.  

If your main interest is home theater and you don't need some of the extra connections available on the 8805, I would get the 7704 or 7705.  For home theater I can't tell any difference between the 8801 and the 7704.  It seemed like the 8801 sounded better than the 7704 for 2 channel, but not dramatically better. 

Supposedly the 8805 sounds better than the 8801.  I have not had an opportunity to compare.  If 2 channel listening is important, then it may be worth the money to get the 8805.  You might be able to pick up an AV8802 for about half the price of the AV8805.  I've seen some used ones here and some refurbished ones on a couple of web sites.

My preference is for 2 channel listening and I use a Modwright LS100 for 2 channel and use the HTBP function to send amplification to the AV7704 for movies. 

A good quality 2 channel preamp should sound significantly better for 2 channel listening.  It depends on your listening preferences and space considerations.

This is an area where I do think the technology has brought the price down. Before the home theatre phenomenon bloomed in the '90s, i was using a variety of processors, including Lexicon, Fosgate, etc. When discrete multi-channel was standardized I bought Meridian components, which were fairly expensive and a pain to program. The Meridan eventually grew long in the tooth, replaced by McIntosh and then eventually to a box shop mid-range Marantz, which at least for HT purposes (I don't use it for music), sounds better, is easier to program, has a basic form of room correction and is a fraction of the price of the earlier 'state of the art' pre-pros. I guess there is still a market for those, but at least for my use, after having had some big, fancy HT projection systems with full sized racks of equipment for line doubling, amplification, woofer servo control (old Velodyne) and assorted other components, I enjoy the simplicity of a much more modest flat screen, pre-pro, multichannel amp and modest satellite array with a decent subwoofer. Fraction of the price. Remember the Faroujda components that cost well over 10k US for upscaling? Now a cheap chip installed in most TVs and processors. Perhaps my standards are lower now- I gave up laser disc, DVD, Blu, etc. and just stream movies. The prices on HT gear do seem to have come down as performance has increased. 

If I were you I would get the Marantz AV8805 over the Mac MX122. If you want to go with Mac I suggest you look at the MX160 as this will be a step up sonically than the AV8805 or the MX122. However, the Marantz & the Mac MX122 are very good for HT but aren’t good enough for 2ch music playbacks IMO.
The MX160 might be good enough for your 2ch listening needs depending on your expectation when it comes to stereo listening to music. Another processors that will perform well in 2ch will be the Classe SSP 800 & Classe Sigma SSP, Krell Evo 707, 1200U and possibly the Krell Foundation series, Cary Cinema 12, Bryston SP4/SP3, Meridian Reference 861 v8.

The Mac MX122 was based on the Marantz AV8802. They only shared same base platform, HDMI boards, GUI, OSD & firmware as well as remote. But Mac built its own power supplies, DAC, clock, digitall and analog audio circuitry, analog audio output stages, voltage regulator, etc.

If 2ch is important to you I suggest you look at a high end stereo preamp with HT bypass feature. But you should also get a good dedicated stereo or monoblock power amps for your front 2ch speakers if 2ch listening is of important to you.
While your Mac MC8207 seven-channel amp is fine for HT but it isn’t good enough for 2ch listening to music.

I did go with the Marantz AV8805 for my HT because I could not pass up the deal I got from the authorized Marantz dealer. I wanted to have a preamp that had all the latest technology built inot it and be of a good brand with a good reputation(also I grew up having Marantz) so little nostalgia there. 

As for the Amp which is the MC8207 that is rated at 200W into 8 Ohms, wouldn't it give me the same 2 ch listening as to having a dedicated 2 channel McIntosh Amp that is rated at the same in power? Even though I don't think Mac has any new 2 channel amp that is 200w x 2, it's either 150x2 or 300x2 so no doubt that the 300x2 would be better than the mc8207

For your stereo listening you can get a high end very good stereo integrated amp. Doesn't have to be stereo separates. Really good stereo integrated amp such as the Gryphon Diablo analog integrated amp (expensive) but you will need a very good front end source components to go with that. There are other countless options out there. 
Do you have a turntable? If you only had a digital front end source components you should consider getting either a PS Audio DirectStream DAC with a very good streamer and transport, various Naim DS, either Linn Akurate or Klimax DS, etc.
Again there are countless other options out there.