The new Onkyo 705 gives you 3 hdmi (1.3a) inputs, 100 watts per channel (7.1) + 2 more in zone 2 and Thx Select 2 certification. It just like all the newest Onkyos also does the external decoding of True HD and DTS HD MA....For 550-600 bucks (on normal sale prices).
805 vs 705
The main draw of the 805 over the 705 is gives ultra THX cert while 705 gives you select 2 THX and 605 gives you no THX. Ultra THX cert is for big rooms, select 2 is for mid/small rooms. (I find myself using Pro Logic IIx most the time anyway) Also each receiver gives you 30 more watts per channel of power. (70,100,130). (for the units 605, 705, 805 respectively)
705 vs 605
The reason to get 705 over the 605 is again of course, watt increase, THX cert, extra hdmi input.. lol.. and of course the glowing blue volume ring!
905 vs (605, 705, 805)
The reason to get the 905 over all the other models is the HDMI upconvertion to 1080p ... analog and digital sources at a lower resolution can be outputted via hdmi at 1080p. The 605, 705, 805 all cannot do this.. and they actually downconvert higher resolution analog sources being pushed through HDMI. However all these units can do pure HDMI pass through without changing the resolution.
Reason I like 705 out of this lineup:
Biggest reason is great price for high quality:
The 705 doesn't overheat like the 805 and 905 does (no reported overheats in out 705 circle yet). (These 805/905 units tend to get way more heated up and users report automatic system shut downs, or increased popping) however, because the 705 was built after the 805 and after the 605 and has a more efficient power supply then both of them. It consumes as much power as the 605 even though its pushing 30 watts per channel more. (Tests done with KILL A WATT meters on all 3 units at same volume load) The best part is, people (including myself) have bought it for 550 bucks.. usually around 600ish. The 905 costs quite a bit more in the lineup and the 1080p upconvert is nice.. in my mind its a better reasons to spend more money from the 705 then the 805 is. The 605 and lower without THX certification is just low on my list because of that reason.
Also if you have hearing problems this 705 will get PLENTY loud at 100 watts per channel... it also sounds very clear... these new receivers from Onkyo are sweet over last generation of receivers.
Does the 875 have HDMI upconversion to 1080p ??