About as confused as you can get

[bklyn1028]

What I have:
Sony KDS R70 XBR2
PS3
OPPO DVD
Explorer 8300 HD DVR cable box
Yamaha HTR 5150
Yamaha speakers for surround, Front speakers are Argonaut by Mission
my dilemma:

Toying with a new receiver (yamaha works flawlessly but 5.1 only and no hdmi). It would be nice to have hdmi into a new receiver then to tv and use one remote, but....would the sound be that much better in a new one with Dolby True HD and DTS HD? Price isn't that much of an issue, but would like to be in the less than $1k range. Or am I wasting my time because I won't hear that much of a difference in sound with a new receiver.
Any help would be terrific
Thanks