Question about DPP vs PS CS3 for RAW

I just upgraded from PS Elements to CS3. And I just changed my color mode on my 5D from sRGB to Adobe RGB thinking I could handle the Adobe RGB workflow... maybe I better read up first.

When I open my RAW files in DPP the color and toning look great. When I open in PS CS3 Cam RAW, they look rather bland. What's the difference? I can see Adobe RGB 1998 is the color profile by default with these files in PS. Is there a setting I should tweak, or is this just a view of default data in PS that I must do normal editing vs smarter Picture Style data in DPP that already profiles for me when I open the file in DPP Viewer?

Also, I see a "Camera Calibration" tab in PS Camera RAW, are there 5D profiles anywhere, or something I just should play around with until I get it right?

A few possibilities:
First, check if you've set up your color management right in PSCS3. Link
DPP applies camera settings as default (for instance sharpness, contrast and saturation) ACR does not.

On the camera calibration: Here is a read.

Thanks, problem solved from your info. I read much your sticky last week, but never completed the change to preferences. Now I'm diving all the way into color management! Blame it on my Epson Pro 3800...