The Oppo is a good choice for performance if you have HDMI or DVI inputs (the component output is limited to 480i on the Oppo, which is why it is generally recommended only for displays with HDMI or DVI). Denon is a good brand, but if your budget isn't up for a mid-level Denon you might try Toshiba. If you spend a good chunk of change on a Denon, it should go for the seven years you are hoping for. The Oppo's too new for us to know how it'll last long-term, but I haven't heard of units failing after a year of growing popularity online so they can't be skimping too badly on build quality - and at $200 (as compared to $350-$750 for a Denon that isn't overly stripped down), it's not so big an investment you couldn't replace it after three or four years if it did give up the ghost.

The 990 has some nice DAC's, and with the upsample capability it really does a good job with CD's in stereo. You could probably use your DVD player as a CD transport and get some very pleasing results.