Yes. I started using X-Rite i1. The changes I see on my display (HP w2408h) are subtle, but enough to make it worth the trouble.
Also, at the Chromoholics web site,
http://www.fors.net/chromoholics/, you can find a download for a script that runs in Photoshop to adjust your image for errors in the way the sensor in your camera reads colors. The download is free, but you need to buy the ColorChecker chart by X-Rite (about $70). This only works if your shooting RAW images.
My prints are coming out very close to what I see on screen using printer profiles for my paper, so I haven't gone through the trouble of trying to profile my printer also.