OK. Maybe I should let you know which equipment I'm using. I have a PC, Sony Artisan monitor, Gretag Eyeone2 display for calibration, Canon 30D and PS2. And now Lightroom but I just started using it. I do work in 16-bit.
Actually, my issue isn't when I export a file embedded with the ProphotoRGB profile to Photoshop CS2. The color is fine on screen. My monitor is quite good actually for those who are familiar with the Artisan. The problem is when I convert to Adobe 1998 or SRGB. Completely desaturates and and clips colors big time. It is a problem for me because I don't have an Epson printer or anything at home. I have to use a lab. I was actually at hard copy proofs to test my display and they said their color space is SRGB. So, I need to be able to convert. Or should I just leave it and let their lab do the conversion? My guess is that it won't look pretty.
Also, for just converting from Prophoto to sRGB and then, voila, you're done. That doesn't work for me. Even, in my old workflow, from when I used Digital Photo Professional to convert from RAW or CR2 files then I exported to Photoshop. My color space in photoshop is Adobe 1998. When I 'save for web' there is still a little tweeking that I have to do to make it look as close as possible to the 16-bit TIF embedded with Adobe98. BUT, it is possible and much easier because the difference between Adobe 1998 and sRGB aren't as vast as Adobe98 and Prophoto.
This is the kink I'm trying to work out. Maybe the Prophoto profile has been used for years but it is new to me. I've always used Adobe1998 because of it's safer ability to convert to CMYK. I've also been an owner of Martin Evening's Photoshop books and have my color management set up like him because he is a fashion/beauty photographer mostly and I do mostly that as well.
But maybe I'm missing a step here? That's why I posted. To see what other photographers are using as a workflow for Lightroom.