I happened to end up chatting with HP's "architect" for their imaging and printing systems. I learned a bunch of neat stuff.

- Use HP paper with an HP printer. Use Epson paper with an Epson printer. Tell your print software the exact model of paper that you're using. They measure the daylights out of their own papers and carefully tune the ink they send to look beautiful for their own paper. They treat other paper as "generic" and do something that won't totally suck.

- Print in "best" quality mode rather than "normal" or "draft". It will take longer, potentially much longer, but the printer has the chance to deposit more ink, giving you deeper blacks and more saturated colors.

- Modern inkjet paper is a marvel of technology. They use superabsorbent materials on the paper coating to suck up the ink and keep it from spreading. This allows them to deposit much more ink than they might be able to do on traditional paper, where it would smear out and soak through.

That said, I have an HP DeskJet 970Cxi. It's got a nifty two-sided printing feature, and runs amazingly fast in "draft" mode, but it's photo-quality prints aren't as good as the "photo" printers. If you want to maximize photo quality, the six-ink Epsons are probably the way to go. If you want a printer that's also going to be cranking out code or other generic stuff, and then occasionally does high quality prints, I'm quite happy with my printer.