I doubt the Onkyo + other receivers reviewed in What HIFI are going to cope with music as well as your TAGs.
I demo'd the Onkyo 875 against my Audiolab 8000AV + 8000 X7 pre + power processor for CDs and there was (to my ear) a noticeable difference in favour of the Audiolab. And your TAG is a (few) step(s) up from my Audiolab.
Having said this, the Onkyo will obviously upscale better than the Tag(!) Depends on what is more important to you. Alternatively you could use the DVD machine that you will buy to upscale DVDs but unlike the Onkyo it will not upscale everything (e.g. TV and Sky pictures)
Urban T may be able to better advise - I think I read somewhere that he moved from the same processor as you to the Onkyo 875 (although from memory he had a different power amp - a Lexicon I think).
Both Denon DVDs will play CDs and play movie sound effects better than the Oppo. If you are considering the Denon 2930, go for the Marantz DV7001 instead. You can probably get it (slightly) cheaper and it plays CDs better.
The best advice might be to wait until Christmas if you can. The other manufacturers haven't really reacted to the Onkyo receivers. It may be that some of them produce something with similar features but better sound (as they now need to beat the new benchmark).
If nothing else, waiting will allow you to pick the items up more cheaply