AVS scaled my image down, but you can see a couple key things. One, my four-core Phenom II X4 3.0ghz is taxed to about 50%, but not evenly across cores. I'd guess that something as cheap as the $100 Athlon II X4 2.9ghz would run this fine, but don't quote me on that. Paired up with my Geforce GTS 250, which is not an expensive card by any means, Wind Waker runs at a perfect, smooth 30fps at 1920x1080. The game seems to be hard capped at 30fps, unable to go any higher. A second thing you'll notice in Wind Waker specifically is that it is rendering different parts at different resolutions. Anything close with no filters run at the full 1080p, but distance items seem to have a depth-of-field filter over them running at 480p. It's odd, and simply an emulation artifact. Keep in mind that I just fiddled with it for 5 minutes. This may be an easily solvable issue by visiting the Dolphin forum and reading the Wind Waker thread.
Overall, Dolphin has come a long way since I looked at it last. It feels very much like ePSXe right around when Final Fantasy 9 came out. Very complete feeling, with some obvious non-critical issues left to resolve.
Oh, and the sound is still a bit chunky feeling. I'm not starving it of CPU to use anymore, so I'd guess that the sound engine is still a bit rough. Again, maybe it's something addressed on their forum though.
I think I'm going to look into some Wii action next. Mario Galaxy 1 would be pretty amazing to go through again at 1080p. I need to scrounge up a Bluetooth dongle and a wireless sensor bar now.
Oh, and I run dual monitor, so the split in the image is real time. Full screen emulation screen, with the CPU monitor running on the second screen.