Recently I bought a new computer and 24" LCD monitor. I downloaded new Epson profiles for my R1800 printer, and I calibrated my monitor with Spyder 3 Pro.
The good: My prints almost perfectly match my monitor profile. I'm very happy with these results and can probably live with them forever. I let Photoshop (CS3) control the color and I use the Epson printer profile in the driver. So far so good.
The bad: When I soft-proof the image using the appropriate printer profile the image looks much darker and muddy. If I modify the image to look better in the soft-profile it is completely screwed up in the print.
This is a new problem for me. With the old computer the soft-proof matched up quite well with my monitor profile.
The soft proof image is just an estimation and is usually not very accurate.
Photoshop:
Device To Simulate Specifies the color profile of the device for which you want to create the proof. The usefulness of the chosen profile depends on how accurately it describes the device’s behavior. Often, custom profiles for specific paper and printer combinations create the most accurate soft proof.